# Calculate the enthalpy for

25,110 results, page 10

### chem

24. Hydrogen peroxide can decompose to water and oxygen according to: 2H2O2 (l) + -----------> 2H2O(l)+ O2 (g) ^ H = -196 kJ What is the enthalpy change accompanying the reaction of 5.00 g H2O2 (l) according to the above mentioned reaction ?

### chemistry

24. Hydrogen peroxide can decompose to water and oxygen according to: 2H2O2 (l) + -----------> 2H2O (l) + O2 (g) ^ H = -196 kJ What is the enthalpy change accompanying the reaction of 5.00 g H2O2 (l) according to the above mentioned reaction ?

### Chemistry

The thermochemical equation for the combustion of hexane is shown below. 2 C6H14 (g) + 19 O2 (g) → 12 CO2 (g) + 14 H2O (g) ΔH° = –8326 kJ What is the enthalpy change for the combustion of 0.650 L C6H14 at STP?

### Chemistry

How much energy, in calories, does it take to convert 20.0 grams of solid water, at 0.0 degrees C, into liquid water, at 0.0 degrees C? (The enthalpy of fusion for H2O is 1.44 kcal/mol)

### college physics

Consider two vectors A = 4i - 4j and B = -i - 8j . (a) Calculate A + B. (b) Calculate A - B. (c) Calculate absolute value(A + B). (d) Calculate absolute value(A - B). (e) What is the direction of A + B? (from the +x axis) (f) What is the direction of A - B? (from the +x axis)

### Physics

i41 tinypic com/2qna74k png (add the periods) For the vectors in the figure, with a = 6.4, b = 2.5 and c = 6.87. Calculate a(dot)b calculate a(dot)c calculate b(dot)c I got 0 for a(dot)b but the same method (ac*cos(theta)) does not work for the other two, please help.

### Programming in Java

Write a program to calculate adjacent and opposite of a triangle. My code can calculate hypotenuse but won't calculate opposite and adjacent.

### Chemistry

The enthalpy change in the combustion of the hydrocarbon octane is delta H = -5.48 x 10^3 kJ/mol C8H18 (l). How much heat, in kilojoules, is liberated per gallon of octane burned? (Density of octane = 0.703 g/mL; 1 gal = 3.785 L.)

### Physics I NEED HELP WITH EQUATIONS

A 7kg block is pulled at a constant velocity by a horizontal 25 N force - Calculate normal & gravitational forces - Calculate the applied & frictional forces - Calculate the coefficient of friction CAN SOMEONE PLEASE HELP ME WITH THE EQUATIONS FOR ALL OF THESE THINGS?

### Chemistry

A 4.50 g sample of LiCl at 250 C dissolves in 25.0 ml of water also at 25.0 C.? The final equilibrium temp of the resulting solution is 60.8 C. What is the enthalpy of solution, deltaHs, of LiCl expressed in kilojoules per mole.

### chemistry

Suppose you do not know the enthalpy of decomposition of the process: CaCO3 = CaO + CO2 Explain in terms of thermodynamic parameters why heating to a high temperature might turn this decomposition to a spontaneous process.

### Chemistry

I did a lab and got a bunch of questions about the lab. Here is what my lab was about: Properties of alcohols: First, I wrapped the bulb of a thermometer with a tissue secured with a wire. Then I squeeze enough methanol onto the tissue to completely saturate. At the same time...

### Chemistry

Hello Jiskha, I'm hoping you are able to help me with my homework. Its on General Chemistry. Question One - When the solid NH4NO3 is dissolved in water at 25 C, the temperature of the solution decreases. What is true about the signs of enthalpy (H) and (S) for this process? ...

### SCIENCE

when 10.0 ml of .012 M PbNO32 is mixed with 10.0 ml of .030 M KI, a yellow precipitate of PbI2 forms. calculate the initial molarity of Pb+2 calculate the initial molarity of I- On measuring the equilibrium concentration of I-, it came out to be 8.0 x 10^-3 M. Calculate the ...

### chemistry

hello i was just trying this problem for my college class and its kinda hard. I got up to the last part, but I can't figure it out.. Impure nickel is refined by smelting sulfide ores through mond process: Ni (s) + 4CO (g) --> Ni(CO)4. There's like 8 parts to this problem. ...

### Physics

1. The total enthalpy of 15.000kg of steam at 2250.000kPa is 34191.510kJ. Determine the dryness of the steam. ANS = % Not sure where to start. I need a little help please. I do have a chart with the properties of saturated steam. Thank you.

### Thermodynamics

1. The total enthalpy of 15.000kg of steam at 2250.000kPa is 34191.510kJ. Determine the dryness of the steam. ANS = % Not sure where to start. I need a little help please. I do have a chart with the properties of saturated steam. Thank you.

### chemistry

A constant volume (bomb) calorimeter was calibrated in an analytical laboratory by burning 1.057g of benzoic acid (C7H6O2) which has an enthalpy of combustion of -3228 kJ/mol. The temperature of the calorimeter rose from 22.75°C to 29.00°C. What is the heat capacity of the ...

### chemistry-URGENT

Hydrazine is used as a rocket fuel. When 1.50 g of hydrazine, N2H4, was burned in a bomb calorimeter, temperature increased from 23.57 °C to 28.84 °C. The heat capacity of the calorimeter was 5.510 kJ/°C. Determine the enthalpy of combustion of octane.

### chemistry

State whether each of the following will increase,decrease or unchange when catalyst is added to the reaction and give an explanation for your answer please a) rate of reaction b)activation energy c)reaction enthalpy d)equilibrium of reaction

### Chemistry

In a calorimeter, 100 g of ice melts at 0oC. The enthalpy of fusion of the ice is 334 J/g. How much heat was absorbed? 33.4 J 334 J 33.4 kJ 334 kJ

### chemistry

A certain reaction is spontaneous at 72˚C. if the enthalpy change for the reaction is 19Kj/mol, what is the minimum value of ΔS (in J/K•mol) for the reaction?

### Chemistry- helpp!

The equation for synthesis of the poisonous gas COCl2 is CO(g) + Cl2(g)COCl2 If 43.2 kJ of energy is evolved when 39.5 g of COCl2 is synthesized, what is the molar enthalpy for this synthesis? THANK YOU!

### chemistry

why does the enthalpy of formation for the ethanol dimer have more energy than two isolated ethanol molecules? is it because there is a bond between the hydrogen of ethanol dimer

### 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.

### 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 ...

### 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?

### 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?

### 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 ...

### 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 ...

### 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?

### Chemistry

Write the balanced chemical reaction (showing appropriate symbols and states) for the chemical reaction with enthalpy change equal to and defined by the quantity dHformation [NH3(g)] N2(g) + 3H2(g) --> 2NH3(g) Is that all the question is asking for?

### physics

a car of mass 1000 kg moving at a speed of 20 m/s is brought to rest through a distance of 100 m by applying the brakes.a)calculate the accleration of the car.b) calculate the force by the brakes assuming that is constant and there is no other resistance.c)calculate the work ...

### 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.

### 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?

### 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 ...

### 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 ...

### 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 ...

### 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 ?

### 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?

### 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)

### 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

### 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

### 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 ...

### 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 ...

### 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.

### 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

### 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.

### 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

### 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

### 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.

### 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 ...

### 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 ...

### 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?

### 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?

### 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

### 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

### 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 ...

### 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

### 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 ...

### 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 ...

### 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 ...

### 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

### 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...

### Chemistry

The enthalpy of combustion of benzoic acid (C6H5CO2H) is -3228 kJ/mol. The burning of 1.698 g of benzoic acid in a calorimeter causes the temperature to increase by 2.865°C. What is the heat capacity (in kJ/°C) of the calorimeter?

### Chemistry

The enthalpy of combustion of benzoic acid (C6H5CO2H) is –3228 kJ/mol. The burning of 1.698 g of benzoic acid in a calorimeter causes the temperature to increase by 2.865 ºC. What is the heat capacity (in kJ/ºC) of the calorimeter?

### 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 ...

### 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

### 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=

### 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

### 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 ...

### 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 ...

### 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...

### 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

### 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

### 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

### 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...

### 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)

### 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 ...

### 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 ...

### 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 ...

### 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. ...

### 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...

### 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...

### 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 =???

### 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?

### 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 ...

### 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 ...

### 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 ...

### 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?

### 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?

### 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

### 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...

### 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?

### 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 ...

### 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 ...

### 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 ?

### 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?

### 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?