Saturday

December 10, 2016
Number of results: 24,023

**Chemistry**

Which of the following is(are) true for an exothermic reaction? [H = enthalpy] A) ƒ´H¢X > 0 B) ƒ´H¢X < 0 C) Hreactants > Hproducts D) Hreactants < Hproducts E) Hreactants = ƒ´H¢X The square means delta.

*January 30, 2011 by Joseph*

**chemistry please help **

the enthalpy change when a strong acid is neutralized by base is -56.1 kJ/mol. If 135 ml of .450 M HI at 23.15 C is mixed with 145 of .500 M NaOH at 23.15 C What will the max temperature reached by the resulting solution? tamana: Assume the specific heat is 4.18 J/gC and ...

*October 17, 2010 by Jazmin*

**Chemistry **

Compound A is added into a calorimeter that contains 0.750 litres of water. If the dissolution of 5.0 g of this compound causes the temperature of the water to rise to 45.0 °C, what is the enthalpy of solution of compound A?

*October 9, 2012 by Marlee*

**Chemistry **

Compound A is added into a calorimeter that contains 0.750 litres of water. If the dissolution of 5.0 g of this compound causes the temperature of the water to rise to 45.0 °C, what is the enthalpy of solution of compound A?

*October 9, 2012 by Marlee*

**Chemistry**

20cm3 of 0.500moldm-3 H2SO4 was consumed to neutralize 50cm3 of 0.400moldm-3 NaOH. The temperature of the system is increased by 36 degree C. The heat capacity of the calorie meter was 39 JK-1, and the heat capacityof the solution is 4.2JK-1. Find the enthalpy of ...

*February 21, 2013 by Emma*

**Chemistry**

20cm3 of 0.500moldm-3 H2SO4 was consumed to neutralize 50cm3 of 0.400moldm-3 NaOH. The temperature of the system is increased by 36 degree C. The heat capacity of the calorie meter was 39 JK-1, and the heat capacityof the solution is 4.2JK-1. Find the enthalpy of ...

*February 21, 2013 by Emma*

**chemistry**

Sn (s) + 2Cl2(g) --> SnCl4(l).Sn(s) + Cl2(g) --> Sn Cl2(l) DH = -186.2 kJSnCl2(s) + Cl2(g) --> SnCl4(l) DH = -325.1 kJWhat is the change in enthalpy?

*March 9, 2013 by Sammantha*

**Enthalpy of a Phase Change**

How many grams of ice at -20.1C can be completely converted to liquid at 9.9C if the available heat for this process is 4.58×103 kJ? For ice, use a specific heat of 2.01 J/(g*C) and Heat of Fusion is = 6.01 kJ/mol.

*November 8, 2009 by Wessells*

**chemistry**

Ammonia, NH3, is used as a refrigerant. At its boiling point of -33ºC, the enthalpy of vaporization of ammonia is 23.3 kJ/mol. How much heat is required to vaporize 125 g of ammonia at -33ºC?

*May 12, 2010 by b*

**AP Chemistry**

These are some lab questions from the following lab: Vapor Pressure and Enthalpy of Vaporization of Water 1. Why does vapor pressure change with temperature? 2. The assumption was made that the vapor pressure of water is negligible at a temperature close to zero. Find the ...

*January 28, 2007 by anonymous*

**Chemistry**

If 12.50 grams of Pb(NO3)2 are reacted with 3.18 grams Nacl in a "typical double displacement" reaction, please calculate the following: a) What is the limiting reagent? b) what is the reagent in excess? c) Calculate the mass of the excess. d) Calculate the theoretical yield ...

*April 6, 2008 by Larissa*

**Chemistry**

My assignment sheet said to plot a KE distribution diagram where 10% of the molecules meet or exceed the Ea. I know the Ea and enthalpy change. But nothing else so does this mean the diagram is just a estimation of what it would look like.Or am i doing something wrong... Plz ...

*December 14, 2012 by Sky*

**Chem**

The brown color associated with photochemical smog is due to NO2(g). This is involved with the following equilibrium in the atmosphere: 2 NO2(g) <===> N2O4. Predict the signs of the enthalpy and entropy changes for this reaction. If the equation is at equilibrium should ...

*March 30, 2008 by Ginger*

**chem**

The complete combustion of butane, (g) is represented by the equation C4H10+ 13/2O2->4CO2+5H2O standard enthalpy is -2877kj How much heat, in kilojoules, is evolved in the complete combustion of 12.8ml at 23.8degrees celsius and 744mmhg ?

*October 8, 2008 by tomi*

**Chemistry**

AgCl >Ag + Cl The silver metal that is formed causes the lenses to darken. The enthalpy change for this reaction is 3.10 102 kJ/mol. Assuming all this energy must be supplied by light, what is the maximum wavelength of light that can cause this reaction?

*October 21, 2008 by Giznelbell*

**Biophysical Chemistry**

The combustion of 1 mole of C2H5OH (Ethanol) in a bomb calorimeter produces 1364 kJ/mol at 25 degree Calcium. What is the value of enthalpy chamge for the following combustion reaction? C2H5OH(l) + 3O2(g) => 2CO2(g) + 3H2O(l)

*December 21, 2010 by Laura *

**Chemistry**

The standard enthalpy of formation of Mn2O3 is −962.3 kJ/mol. How much heat energy is liberated when 4.7 grams of manganese are oxidized by oxygen gas to Mn2O3 at standard state conditions? Answer in units of kJ

*October 7, 2012 by Sam*

**AP Chemistry**

The standard enthalpy of formation of Mn2O3 is −962.3 kJ/mol. How much heat energy is liberated when 6.5 grams of manganese are oxidized by oxygen gas to Mn2O3 at standard state conditions? Answer in units of kJ

*October 24, 2013 by Gabriella*

**chem**

For substance A the emlting point is 16.61 degrees C and the specific heats of the solid and the liquid form are 2.662 and 5.188 JgC respectively. It requires 38600 joules to move 120g of A from 0 degrees C to 32.5 degrees C. This leads to the conclusion that the enthalpy of ...

*February 1, 2009 by Amanda*

**Physics**

A cannon ball is fired at 50 m/s at a 37 degree angle above the horizontal. Calculate the time the cannon ball in the air, calculate how high it rises and calculate how far from the cannon the ball lands? Answers: 6.14 s, 46.2 m, 245.2 m

*November 13, 2012 by Victoria*

**Chemistry **

How much heat is required to convert 32.5 grams of ethanol at 28 C to the vapor phase at 78 C? Ethanol (C2H5OH) boils at 75 C. Its density is 0.789 g/mL. The enthalpy of vaporization is 38.56 kJ/mol. The specific heat of liquid ethanol is 2.3 J/g-K.

*February 11, 2010 by Anonymous*

**Physics**

A 245 g particle is released from rest at point A inside a smooth hemispherical bowl of radius 35.0 cm, as shown in Figure 5-21. (a) Calculate the gravitational potential energy at A relative to B. 1 . (b) Calculate the particle's kinetic energy at B. 2 (c) Calculate the ...

*October 20, 2011 by Brooks*

**Health Finance**

Question Details Consider the following 2007 data for Newark General Hospital (in millions of dollars): Static Flexible Actual Budget Budget Results Revenues $4.7 $4.8 $4.5 Costs 4.1 4.1 4.2 Pro?ts 0.6 0.7 0.3 a. Calculate and interpret the pro?t variance. b. Calculate and ...

*January 26, 2012 by molamidi*

**Chemistry **

What is the value of q when 8.21g of water vaporizes at 373 K? The enthalpy of condensation of water at 373 K is -40.7 kJ/mol. I tried using the equation q= m x Cs x Delta T, but I never got the right answer which is 18.5 kJ apparently, so I need to find out what I did wrong.

*February 4, 2013 by Sarah*

**Ap chemistry**

The standard enthalpy of formation of Mn2O3 is −962.3 kJ/mol. How much heat energy is liberated when 6.4 grams of man- ganese are oxidized by oxygen gas to Mn2O3 at standard state conditions? Answer in units of kJ

*October 29, 2013 by Gabriella*

**chemistry**

Using the following thermochemical data, what is the change in enthalpy for the following reaction? Ca(OH)¿(aq) + HCl(aq) d CaCl¿(aq) + H¿O(l) CaO(s) + 2HCl(aq) d CaCl¿(aq) + H¿O(l), DH = -186 kJ CaO(s) + H¿O(l) d Ca(OH)¿(s), DH = -65.1 kJ

*May 5, 2013 by ciara*

**Chemistry **

At its normal boiling point of 126°C n-octane, C8H18, has a vapor pressure of 760 torr. What is its vapor pressure at 25°C? the enthalpy of vaporization of n-octane is 39.07 kj/mol.

*December 11, 2015 by Nicole*

**chemistry**

A studen is asket to calculate the amount of heat involved in changing 10.0 g of liquid bomine at room temperature (22.5 C) to vapor at 59.0 C. To do this, one must know specific heat (0.474 J/g*C), boiling point (59 C), and heat of vaporization (29.6 kJ/mol) of bromine.In ...

*March 30, 2011 by Lena*

**Chemistry 2**

A titration is performed by adding 0.124 M KOH to 40 mL of 0.159 M HNO3. a) Calculate the pH before addition of any KOH. b) Calculate the pH after the addition of 10.26, 25.65 and 50.29 mL of the base.(Show your work in detail for one of the volumes.) c) Calculate the volume ...

*April 2, 2013 by Antonio*

**Physics**

A ball rolls off the edge of a 0.75m high lab table with a horizontal speed of 1.50 m/s. Calculate the time that the ball is in flight, calculate the vertical velocity of the ball just before striking the floor, and calculate the horizontal distance(range) that the ball will ...

*April 16, 2015 by Daniel*

**Chemistry**

When 10.0 g of ammonium nitrate (molar mass= 80 g/mol) are dissolved in 1.00 L of water in a bomb calorimeter with a heat capacity of 2.30 kJ/ K, the temp drops 1.52 K. What is the molar enthalpy of solution of ammonium nitrate?

*October 20, 2012 by Sam*

**Chemistry**

Do you expect CaCl(s) to be stable if the 1st ionization energy of Calcium is approx. 590 kj/mol, the Lattice Energy is approx 700 kj/mol and the total change in enthalpy is -36? Why?

*October 14, 2014 by Mary*

**chemistry**

The complete combustion of ethanol, C2H5OH (FW = 46.0 g/mol), proceeds as follows: C2H5OH(l) + 3 O2(g) → 2 CO2(g) + 3 H2O(l) ΔH = −555 kJ What is the enthalpy change for combustion of 15.0 g of ethanol

*October 22, 2015 by sharon*

**chemistry**

In an adiabatic coffee cup, a 75mL of 1.0M HCl and 50mL of 1.0M HaOH were neutralize. The initial temperature is 22.1 C and the final temperature is 26.3 C. What is the enthalpy? S=4.18g/JC and the heat capacity of the adiabatic coffee

*November 30, 2016 by KO*

**chemistry**

It is ok to have a negative percent error? I got a negative value for the percent error of the enthalpy of the formation of methane gas

*July 20, 2014 by Liz*

**Chemistry**

20cm3 of 0.500moldm-3 H2SO4 was consumed to neutralize 50cm3 of 0.400moldm-3 NaOH. The temperature of the system is increased by 36 degree C. The heat capacity of the calorie meter was 39 JK-1, and the heat capacity of the solution is 4.2JK-1. Find the enthalpy of ...

*February 21, 2013 by Emma*

**physics**

A small block of mass m = 225 g is released from rest at point circled A along the horizontal diameter on the inside of a frictionless, hemispherical bowl of radius R = 27.5 cm as shown in the figure below. (a) Calculate the gravitational potential energy of the block-Earth ...

*October 27, 2014 by steve*

**science**

The enthalpy of solution of KBr in water is about +198 kJ/mol. Nevertheless, the solubility of KBr in water is relatively high. Why does the solution process occur even though it is endothermic

*January 17, 2013 by Samantha*

**Chemistry Check**

Determine the missing values of deltaH in the diagram shown below ^ | ^ N2O3(g) + 1/2 O2(g) (Enthalpy)| | ^ | | deltaH= +16.02 | | | | | | 2 NO2(g) | | | ^ | |deltaH=? | | | | | | deltaH=?| | | | | | | | N2(g)+202(g) | Answer: Delta H for the right= 66.36 Delta H for the left...

*October 18, 2014 by Nancy*

**physics**

A 250. MW coal-fired power plant burns fuel with an energy density of 35.0 MJ kg-1. Water enters the temp reduction tower at 293 K and leaves at 350. K at a rate of 4200. kg s-1. 4. Calculate the energy removed by the water each second. 5. Calculate the energy produced by the ...

*March 11, 2010 by needs help*

**physics**

A 250. MW coal-fired power plant burns fuel with an energy density of 35.0 MJ kg-1. Water enters the temp reduction tower at 293 K and leaves at 350. K at a rate of 4200. kg s-1. 4. Calculate the energy removed by the water each second. 5. Calculate the energy produced by the ...

*March 11, 2010 by emily*

**Chemistry**

A 43.0 g sample of hydrated cobalt (II) sulfite is heated to drive off the water. The anhydrous cobalt (II) sulfite has a mass of 26.1 g. Calculate the mass of water. Calculate the moles of water. Calculate the moles of cobalt (II) sulfite. Calculate the mole ratio of water to...

*October 26, 2012 by Elizabeth*

**science chemistory**

CaCO3 2HCl forms CO2 CaCl2 H2O 1.calculate the molar mass of calcium chloride produce 2.calculate the number of moles of calcium carbonate 3.calculate the mass of calcium carbonate

*June 14, 2015 by kem*

**Physics**

A trunk of mass m = 1.100 kg is pushed a distance d = 32.0 cm up an incline with an angle of inclination theta = 26.0 ° by a constant horizontal force P = 150. N. The coefficient of kinetic friction between the trunk and the incline is 0.330. a) Calculate the work done on the...

*October 19, 2012 by Steeve*

**Chemistry**

It's a molar heat reaction lab. 0.07g Mg Mg+2HCl->MgCl2+H2 What is the actual value for the heat of reaction based on the enthalpy's of formation? HfHCl= -118.53 kJ/mole HfMgCl2= -774 kJ/mole

*May 15, 2012 by Nina*

**chemistry help !!!!!!!!!!!!!!!!**

H2(g)+Cl2(g)=2HCL(g) it is found experimentally that 1 mole of H2 gas react with 1 mole of CL2 gas at constant temperature & pressure , to release 184kJ of heat .what is the enthalpy change for this reaction? ∆H=

*January 4, 2013 by john*

**chemistry**

If you need to multiply the following reaction by 2 to be an intermediate reaction in a Hess's law problem, what would be the final value for the enthalpy of reaction you use for this intermediate reaction? C2H4 + 3 O2 2 CO2 + 2 H2O, H = -1410 kJ

*November 24, 2014 by Anonymous*

**physics **

Rotating blade (body force in axial loading) A blade is fixed to a rigid rotor of radius R spinning at omega(w) rad/sec around the vertical z axis, neglect the effect of gravity, calculate the peak stress in the blade calculate the blade elongation. calculate the displacement ...

*May 1, 2013 by mehwish*

**AP Chemistry**

Ammonia, NH3, is used as a refrigerant. At its boiling point of -33 degress Celcius, the enthalpy of vaporization of ammonia is 23.3 kJ/mol. How much heat is required to vaporize 355 g of ammonia at -33 degrees Celcius? a. 1.12 kJ b. 152 kJ c. 251 kJ d. 486 kJ e. 8.27 x 10^3 kJ

*April 4, 2008 by Joe*

**Chemistry 152**

For a certain reaction, the enthalpy change is -148.5 kJ, the entropy change is 256 J/K, and the free energy change is -250.1 kJ. At what temperature is the reaction occurring, in C? Choose one answer. a. 85 b. 102 c. 124 d. 158 e. 210

*July 3, 2010 by Car*

**Mathematics**

(in this question they did not give me any diagrams) use pie 22/7 (a) a piece of wire is bent to form a square of area 121cm squared Calculate the length of each side of the square. Calculate the perimeter of the square. (b) the same piece of wire was bent to form a circle. ...

*June 5, 2012 by INDIANA*

**Physics**

1. Planet X orbits the sun with a mean orbital radius that is 6200 times that of earth. Its diameter is twice that of earth, and its mass is 8 times that of earth. A) Calculate the year of the planet X. B) Calculate the acceleration due to gravity on planet X. C) Calculate the...

*April 22, 2009 by Sandhya*

**Chemistry**

4. A 5.309 g antacid tablet, with CaCO3 as the active ingredient, was mixed was 30.0 mL of 0.831 M HCl. It took 15.3 mL of 0.7034 M NaOH to neutralize the excess acid. a) Calculate the volume of HCl neutralized by the NaOH. b) Calculate the amount of HCl (in mL) neutralized by...

*April 2, 2013 by Josh*

**chemistry 104**

estimate the enthalpy change for each of the following reaction: a) H2C=O(g)+HCl(g .....> H3C-O-Cl(g) b)H2O2(g)+2CO(g).....> H2(g)+2CO2(g) c)3H2C=CH2(g).....> C6H12(g) (the six carbon atoms form a six-membered ring with two H atoms on each C atom)

*November 16, 2012 by oluchi*

**chemistry**

How many liters of hydrogen gas are produced during an enthalpy change of -50kJ, assuming STP conditions? 1L= 1kg zn+ hno3 yields znn03 + 1/2 h2 +100kJ -50 kj x (1mol h2/ 100kj) X (2.02g / 1 mol) h2 ) = 1.01 g please help tried to get the answer but it it supposed to be 11.02 ...

*September 21, 2015 by mariam*

**Chemistry**

3. A liquid hydrocarbon (Cx Hy) is found to be 16.37% H by mass. A 1.158-g vaporized sample of the hydrocarbon has a 358 mL volume at 71.0 C and 749 mmHg. what is the molecular formula for this hydrocarbon? 4. A 1.00 g Sample of C7H603 (s), us completely burned in a bomb ...

*June 21, 2011 by Katrina*

**Physics**

Early skeptics of the idea of a rotating Earth said that the fast spin of Earth would throw people at the equator into space. The radius of Earth is about 6400 km. Show why this objection is wrong by determining the following information. (a) Calculate the speed of a 94-kg ...

*December 3, 2012 by Caleb*

**physics**

Early skeptics of the idea of a rotating Earth said that the fast spin of Earth would throw people at the equator into space. The radius of Earth is about 6400 km. Show why this objection is wrong by determining the following information. (a) Calculate the speed of a 94-kg ...

*December 6, 2012 by Danny*

**Chemistry**

2M +6HCl–>2MCl+3H2 Delta H= -638.0 Kj HClg—>HCl aq= Delta H -74.8 Kj H2+Cl2–>2HCl Delta H -1845.0 Kj MCl3s–> MCl3 aq Delta H -249.0 Kj Use the information above to determine the enthalpy of the following reaction. 2M +3Cl2–>2MCl3 Delta H =???

*March 22, 2013 by Raul*

**Probability and Statistics**

For question 1, here's the numbers you use: {20, 18, 17, 19, 22, 29, 16, 27, 24}. 1. Calculate the 50th percentile. For questions 2 and 3 use this number line: {16, 17, 18, 19, 20, 22, 24, 27, 29, 80} 2. Calculate the z-score for the 80 & explain what it means. (Explain what ...

*January 4, 2013 by Amber*

**Chemistry **

when potassium in water are combined they produced 4000.0 kJ of heat along with potassium hydroxide and hydrogen gas. how much energy would be produced if you dumped a 1.00 kg chunk of potassium into a swimming pool? s this reaction what is the enthalpy change?

*October 19, 2015 by Al*

**Physics**

Early skeptics of the idea of a rotating Earth said that the fast spin of Earth would throw people at the equator into space. The radius of Earth is about 6400 km. Show why this objection is wrong by determining the following information. a.) Calculate the speed of a 103-kg ...

*November 30, 2011 by Matt*

**physics**

Early skeptics of the idea of a rotating Earth said that the fast spin of Earth would throw people at the equator into space. The radius of Earth is about 6400 km. Show why this objection is wrong by determining the following information. a.) Calculate the speed of a 103-kg ...

*November 30, 2011 by Jordan*

**chemistry**

The enthalpy of combustion of benzoic acid,C6H5COOH, which is often used to calibrate calorimeters, is -3227kJ/mol. When 1.236g of benzoic acid was burned in a calorimeter, the tempurature increased by 2.345K. What is the specific heat of the calorimeter?

*November 2, 2008 by annemarie*

**chem**

The normal boiling point of water is 100.00 degrees celsius and the enthalpy of vaporization at this temperature is 40.657kj/mol. What would be the boiling point of water if it were based on a pressure of 1 bar instead of the standard atm?

*November 18, 2008 by tomi*

**Chemistry**

The molar enthalpy of combustion of demand is -6.78KJ/mol.What mass of decane would have to be burned in order to raise the temperature of 500ml of water from 20 degrees Celsius to 55 degrees celsius. I tried using ndeltaH=mcdeltat. But it didn't work. Please help

*October 17, 2016 by Kelvin*

**Chemistry**

The molar enthalpies of combustion of CH3COCOOH(l)CH3COOH(l) and CO(g) are respectively -1275kJ/mol, -875kJ/mol, and -283kJ/mol. What is the enthalpy change for the reaction below? CH3COCOOH= CH3COOH+CO a)1867kJ b)-1867kJ c)117kJ d)-117kJ e)-2433kJ I think it's d) Consider the...

*July 24, 2010 by Bobby*

**Chemistry**

Dioxane C4H8O2 has an enthalpy of fusion = 145.8 Jg-1 and its melting point temp is 11 degrees C. How much energy is required to transform 142g of solid dioxane at 11 degrees C into liquid dioxane, also at 11 degrees C?

*February 1, 2009 by Amanda*

**Chemistry**

I don't really know how to go about this, Please help 1. Calculate the number of moles of the gas. Calculate the volume the gas would occupy at 100.0 C and 15.0 atm. 10.8 g He 2. Given the volume of 54.0 C and 790 torr, calculate the number of moles and mass. 38.1 L CO

*March 11, 2013 by Geoffrey*

**chem**

The complete combustion of butane, (g) is represented by the equation C4H10+13/2O2->4CO2+5H20 STANDARD ENTHALPY IS -2877KJ/MOL How much heat, in kilojoules, is evolved in the complete combustion of 12.8L C4H10 at 23.8degrees celsius and 744mmhg ?

*October 8, 2008 by tomi*

**college chemistry**

The enthalpy of combustion of benzoic acid,C6H5COOH, which is often used to calibrate calorimeters, is -3227kJ/mol. When 1.236g of benzoic acid was burned in a calorimeter, the tempurature increased by 2.345K. What is the specific heat of the calorimeter?

*November 3, 2008 by annemarie*

**chemistry**

a 3.35g sample of solid silver reacted in excess chlorine gass to give a 4.45g sample of pure solid AgCl. the heat given off was 3.95kJ at constant pressure. what is th enthalpy of formation of AgCl?

*June 21, 2010 by Ellie*

**chemestry**

the enthalpy of combustion of benzoic acid C6H5COOH, which is used to calibrate calorimeters usualmete is -3227 kJ mol-1. burning 1.453g of benzoic acid into a calorimeter, the 2,265 ° C temperature increase what is the heat capacity of the calorimeter?

*April 23, 2015 by Daniela*

**physics please help **

A rock of mass 5kg is pushed over the edge of a cliff which is 200m high 1.ignore air resistance and calculate the speed of the rock at the bottom of the cliff. In reality air resistance cannot be ignored. The rock eventually reaches terminal velocity of 30m/s 2.calculate the ...

*April 16, 2015 by Annah van tonder*

**physics**

a ball is thrown straight up with a speed of 8.0 m/s from a third-floor window located 13.0 m above ground. Calculate the maximum height, measured from the ground, of the ball; calculate the ball's velocity when it reaches the ground, and calculate the total time it takes the ...

*October 13, 2014 by Arleen *

**Physics**

2. Charge q1 is located at (0,+30 cm). Charge q2 is located at (0, -30 cm) q1 = +25 pC q2= -75 pC A) Calculate the potential energy of the charges B) Calculate V1, the electric potential at the orgin due to charge q1, and V2, the electric potential at the orgin due to charge ...

*April 12, 2011 by YoungTangerine*

**Chemistry**

Calculate whether or not a precipitate will form if 1.30 mL of 0.80 M NH3 are added to 2.2 L of 1.0 10-3 M FeSO4. Calculate Q.

*March 16, 2012 by Tanya*

**chemistry**

How do I calculate the freezing point of 11.3g FeCl3 in 155g water? I know how to calculate i and m but how do you find Kf?

*December 4, 2012 by Farah Massardi*

**algebra functions**

how do i calculate this if f(x)= 3x+1 and g(x)=x+2 find (fg)(x)and calculate (fg)(2) is this multiplication and if so what do i do first any help would be appreciated

*October 20, 2013 by christin*

**chemistry**

calculate the change in pH when 5 ml of 0.01M HNO3 is added to 50 ml of water. I know how to calculate pH, but not when it is changing.

*April 1, 2015 by Yvonne*

**geometry**

sorry about nos. A(-3, 2) B (5, -4).calculate midpoint. Calculate length of AB, AM, and MB. Thanks again

*April 6, 2015 by robin*

**Chemistry**

calculate kp for the reaction below. PCl3(g) + Cl2(g) ⇌ PCl5(g) How can I calculate it?

*February 14, 2016 by JPR*

**Math**

For f(x) = 3x + 4 and g(x) = x - 1. Calculate (f o g)(x). For f(x) = 3x + 2 and g(x) = x². Calculate (f o g)(-2). Consider the function. f(x)= -2x+1. Find the inverse of f(x). Please help! How do I solve this?

*November 9, 2016 by KC*

**Chemistry**

In a bomb calorimeter, a 6.50 g sample of octane (C8H18) is combusted. The combustion enthalpy for octane is -5.45 MJ per mol C8H18. The temperature change of the calorimeter is 16.5 oC. What is the heat capacity of the calorimeter?

*March 14, 2014 by Mary*

**Math**

The function g and h are defined by g(x) 4x+1/3x-2 and h(x)5x-2 Calculate g(0) 4(0)+1/3(0)-2 = -1/2 Calculate h(1/5) 5(1/5)-2 = -1 Determine the value of gh(1/5) 4(5(1/5)-2) (3(1/5)-2)= 4(-1/-1.4)= 2.85 is this right??

*September 9, 2009 by Keisha*

**Chemistry**

Calculate the weight percent of water in NiSO4 6H2O, how to calculate it?

*December 8, 2010 by Brittany*

**Chemistry**

Calculate the weight percent of water in NiSO4 6H2O, how to calculate it?

*December 8, 2010 by Brittany*

**Chemistry**

Calculate the weight percent of water in NiSO4 6H2O, how to calculate it?

*December 8, 2010 by Brittany*

**chemistry**

for a .001M solution of methionine: a) calculate the isoelectric pH b) calculate the isoionic pH

*April 7, 2013 by Lana*

**Chemistry**

For a solution that is 0.20 M HCN(aq) with a Ka=4.9x10^-10 a. calculate the [H+] b. calculate the [OH-] c. what's the pH? Please show your work on how to solve it. Thank you

*January 27, 2011 by Sharon*

**Grade 12 Advanced Functions**

One zero of f(x)=x^3+4x^2+x+c is -3. a) calculate the value of c. b)calculate the other zeros.

*October 13, 2011 by Rebecca*

**algebra functions**

how do i calculate this if f(x)= 3x+1 and g(x)=x+2 find (f+g)(x) and calculate (f+g)(1) a little confused can some one please help me thank you

*October 20, 2013 by christin*

**chemistry**

Calculate the freezing point of a water solution at each concentration. 1.40m? What are the steps to calculate this?

*November 19, 2014 by Luis*

**Chemistry Plz Help!**

How to calculate dimensional analysis using the density and molarity to calculate the percent (w/w)???

*October 17, 2016 by Barbie *

**Chemistry**

how many Kj of heat are evolved when 6g of pure carbon is completely burned? how many grams of carbon must be burned to furnish 39.3 kJ of heat. enthalpy of combustion of carbon is -393.5

*November 24, 2014 by Shabana*

**Science**

A boy exerts a force of 15N to push a motor bike which has flat tyre for a distance at 30m.calculate the mass of the motor bike. Calculate the density of the motor bike.calculate the work done by the boy.[take g=10m|sm2

*May 14, 2012 by Nicholas*

**Science**

A boy exerts a force of 15N to push a motor bike which has flat tyre for a distance at 30m.calculate the mass of the motor bike. Calculate the density of the motor bike.calculate the work done by the boy.[take g=10m|sm2

*May 14, 2012 by Nicholas*

**Chemistry**

Give the enthalpy change and entropy change values shown below calculate the free energy change for this reaction at 25 degrees C using Gibbs free energy equation. How does this value compare to the free energy change using the standard free energy of formation data? delta H=-...

*May 16, 2007 by Christian*

**physics**

Rotating blade (body force in axial loading) blade is fixed to a rigid rotor of radius R spinning at ω rad/sec around the vertical z-axis. Neglect the effects of gravity. Calculate the peak stress in the blade: σmaxn Calculate the blade elongation: δ Calculate ...

*May 3, 2013 by rka*

**chemistry**

A 10.0 g sample of liquid gallium metal, at its melting point, is added to 50.0g of water. The initital temperature of the water is 24.0 degrees C. If the molar enthalpy of freezing gallium is -5.54 kj/mol, what is the final temperature of the water? Thanks

*November 7, 2010 by Bob*