# Posts by katie

Total # Posts: 2,141

**chemistry**

for n do you have to use the balanced number of before balancing? i would assume balance it first but i wanted to double check

**chemistry**

Calculate the standard free-energy change for the following reaction at 25 °C. 2Au^3+(aq) + 3Ni(s) -->2Au(s) + 3Ni^2+(aq)

**chemistry**

The voltage generated by the zinc concentration cell described by, Zn(s)|Zn2 (aq, 0.100 M)||Zn2 (aq, ? M)|Zn(s) is 23.0 mV at 25 °C. Calculate the concentration of the Zn2 (aq) ion at the cathode.

**chemistry**

Rank these species by their ability to act as an oxidizing agent. Na^+ I2 Cr^3+ F2 Put best oxidizing agent first and continue to have best reducing agent last.

**physics**

The drawing below shows two laboratory carts (each has a mass of 1.0 kg) X and Y in contact with a compressed exploder spring between them. The mass on cart Y is 2.33 kg, distance A is 6 cm, distance B is 9 cm. What mass must be placed on cart X, such that after the explosion ...

**Math**

Use this equation to estimate typing speed, S=w/5-2e, where S is the accurate typing speed, w is the number of words typed in 5 minutes, and e is the number of errors. Choose the letter for the best answer. One of the qualifications for a job is a typing speed of at least 65 ...

**Science**

Na subscript 2SO subscript 4 + CaCl subscript 2 produces CaSO subscript 4 + NaCl Please help me balance this equation and show your work

**MATH**

find the equation of the line tangent to f(x)=2x^3-x^2+1 at x=2. write in point slope form

**chemistry**

A galvanic cell consists of an electrode composed of nickel in a 1.0 M nickel(II) ion solution and another electrode composed of silver in a 1.0 M silver ion solution, connected by a salt bridge. Calculate the standard potential for this cell at 25 °C. Standard reduction ...

**chemistry**

A galvanic cell consists of an electrode composed of nickel in a 1.0 M nickel(II) ion solution and another electrode composed of silver in a 1.0 M silver ion solution, connected by a salt bridge. Calculate the standard potential for this cell at 25 °C. Standard reduction ...

**Chemistry**

Write the equations describing the electrode reactions and the net cell reaction for this electrochemical cell containing tin and silver: Sn(s)|Sn2 (aq)||Ag (aq)|Ag(s) what is the equation for cathode, anode, and net cell reaction

**Chemistry**

Write the equations describing the electrode reactions and the net cell reaction for this electrochemical cell containing tin and silver: Sn(s)|Sn2 (aq)||Ag (aq)|Ag(s) what is the equation for cathode, anode, and net cell reaction

**physics**

Thanks. the impulse is correct but the magnitude of the average force is not.

**physics**

A 220-g ball strikes a wall with a speed of 7.0 m/s and rebounds with only 37% of its kinetic energy. What is the speed of the ball immediately after rebounding? What is the magnitude of the impulse of the ball on the wall? If the ball was in contact with the wall for 9.9 ms, ...

**physics**

a) A set of crash tests consists of running a test car moving at a speed of 12.6 m/s (27.7 m/h) into a solid wall. Strapped securely in an advanced seat belt system, a 69.0 kg (151.8 lbs) dummy is found to move a distance of 0.600 m from the moment the car touches the wall to ...

**chemistry**

The quantity of antimony in an ore can be determined by an oxidation-reduction titration with an oxidizing agent. The ore is dissolved in hot, concentrated acid and passed over a reducing agent so that all the antimony is in the form Sb3 (aq). The Sb3 (aq) is completely ...

**English**

Does Victor have an obligation to the monster? Use evidence from Chapters 9-14 of Volume 2.

**physics**

P is to the left

**english**

Does Victor have an obligation to the monster in Frankenstein? Why?

**MATH**

√5sec²x-2secx=5 i have to solve this equation on the interval [0, 2π).

**physics**

The string in the Figure is L = 135.0 cm long and the distance d to the fixed peg P is 94.5 cm. When the ball is released from rest in the position shown, it will swing along the dashed arc. How fast will it be going when it reaches the lowest point in its swing? How fast will...

**physics**

A 0.40-kg block slides along a small track with elevated ends and a flat central part. The flat part has a length L = 1.84 m. The curved portions of the track are frictionless, but for the flat part the coefficient of kinetic friction is 0.132. The block is released from rest ...

**physics**

A stone with mass m = 2.3 kg is thrown vertically upward into the air with an initial kinetic energy of 190 J. The drag force acting on the stone throughout its flight is constant, independent of the velocity of the stone, and has a magnitude of 2.3 N. What is the maximum ...

**Chemistry**

Calucluate the pH of 100 mL of buffer that is 0.075 M NH4Cl and 0.175 M NH3 before and after the addition of 1.00 mL of 5.05 M HNO3 I have no idea where to even start. HELP!

**Chemistry**

Calucluate the pH of 100 mL of buffer that is 0.075 M NH4Cl and 0.175 M NH3 before and after the addition of 1.00 mL of 5.05 M HNO3 I have no idea where to even start. HELP!

**physics**

With brakes fully applied, a 1660 kg car decelerates from a speed of 74.0 km/hr. What is the work done by the braking force in bringing the car to a stop? What is the change in the kinetic energy of the car?

**physics**

A satellite moves on a circular earth orbit that has a radius of 6.68E+6 m. A model airplane is flying on a 16.3 m guideline in a horizontal circle. The guideline is nearly parallel to the ground. Find the speed of the plane such that the plane and the satellite have the same ...

**physics**

thank you

**physics**

A satellite moves on a circular earth orbit that has a radius of 6.68E+6 m. A model airplane is flying on a 16.3 m guideline in a horizontal circle. The guideline is nearly parallel to the ground. Find the speed of the plane such that the plane and the satellite have the same ...

**chemistry**

At 25 °C, the equilibrium partial pressures for the following reaction were found to be PA = 6.30 atm, PB = 7.20 atm, PC = 6.40 atm, and PD = 9.10 atm. 2A(g) + 2B(g)-->C(g) + 3D(g) What is the standard change in Gibbs free energy of this reaction at 25 °C.

**physics**

With brakes fully applied, a 1660 kg car decelerates from a speed of 74.0 km/hr. What is the work done by the braking force in bringing the car to a stop? What is the change in the kinetic energy of the car?

**physics**

A satellite moves on a circular earth orbit that has a radius of 6.68E+6 m. A model airplane is flying on a 16.3 m guideline in a horizontal circle. The guideline is nearly parallel to the ground. Find the speed of the plane such that the plane and the satellite have the same ...

**Chemistry**

A flask containing a gas was connected to both a closed-end and an open-end manometer. In the closed-end manometer, the mercury in the sealed arm was 755 mm above the level in the arm connected to the fax. In the open-end manometer,the arm connected to the gas was 17 mm higher...

**chemistry**

A flask containing a gas was connected to both a closed-end and an open-end manometer. In the closed-end manometer, the mercury in the sealed arm was 755 mm above the level in the arm connected to the fax. In the open-end manometer,the arm connected to the gas was 17 mm higher...

**chemistry**

Write the balanced chemical equation for each of these reactions. Include phases. However, when additional aqueous hydroxide is added the precipitate redissolves forming a soluble [Pb(OH)4]2–(aq) complex ion.

**chemistry**

Which of the following will be more soluble in an acidic solution than in pure water? AgBr Be(OH)2 RbClO4 CaCO3 PbSO4

**chemistry**

Silver chromate is sparingly soluble in aqueous solutions. The Ksp of Ag2CrO4 is 1.12× 10–12. What is the solubility (in mol/L) of silver chromate in 1.00 M potassium chromate aqueous solution?

**chemistry**

At a certain temperature, the solubility of strontium arsenate, Sr3(AsO4)2, is 0.0510 g/L. What is the Ksp of this salt at this temperature?

**chemistry**

At 25 °C only 0.0580 mol of the generic salt AB3 is soluble in 1.00 L of water. What is the Ksp of the salt at 25 °C?

**chemistry**

A generic salt, AB2, has a molar mass of 159 g/mol and a solubility of 3.30 g/L at 25 °C. What is the Ksp of this salt at 25 °C?

**chemistry**

Write the balanced chemical equation for each of these reactions. Include phases. When aqueous sodium hydroxide is added to a solution containing lead(II) nitrate, a solid precipitate forms. However, when additional aqueous hydroxide is added the precipitate redissolves ...

**chemistry**

Copper(I) ions in aqueous solution react with NH3(aq) according to Cu+(aq) + 2NH3(aq) -->Cu(NH3)2^+ Kf = 6.3x10^10 Calculate the solubility (in g·L–1) of CuBr(s) (Ksp = 6.3× 10–9) in 0.41 M NH3(aq).

**chemistry**

thank you

**chemistry**

I posted a few questions and they all disappeared so i reposted.

**chemistry**

At 25 °C only 0.0990 mol of the generic salt AB is soluble in 1.00 L of water. What is the Ksp of the salt at 25 °C?

**Chemistry**

What additional information would be needed to calculate the rate in units of concentration per time?

**math**

multiply 6sqrt25x^3*sqrt4x^3

**algebra**

multiply 6sqrt25x^3

**physics**

Two blocks with masses m1 = 20.7 kg and m2 = 55.5 kg, shown in the figure, are free to move. The coefficent of static friction between the blocks is 0.74 but the surface beneath m2 is frictionless. What is the minimum force F required to hold m1 against m2?

**Chemistry**

20.7mL of ethanol (density=0.789g/mL) initially at 8.2 degrees Celsius is mixed with 37.1 mL of water (density=1.0g/mL) initially at 25.7 degrees Celsius in an insulated beaker. Assuming that no heat is lost, what is the final temperature of the mixture? This is how I set up ...

**chemistry**

Calculate the change in pH when 6.00 mL of 0.100 M HCl(aq) is added to 100.0 mL of a buffer solution that is 0.100 M in NH3(aq) and 0.100 M in NH4Cl(aq). Calculate the change in pH when 6.00 mL of 0.100 M NaOH(aq) is added to the original buffer solution.

**chemistry**

A cook wants to heat 1.10kg of water from 33 C to 100 C. If he uses the combustion of natural gas which is exothermic to heat the water, how much natural gas will he need to burn? Natural gas produces 49.3 kJ/gram.

**chemistry**

Calculate the change in pH when 6.00 mL of 0.100 M HCl(aq) is added to 100.0 mL of a buffer solution that is 0.100 M in NH3(aq) and 0.100 M in NH4Cl(aq). Calculate the change in pH when 6.00 mL of 0.100 M NaOH(aq) is added to the original buffer solution.

**Physics**

A car that weighs 14600.0 N is initially moving at a speed of 58.0 km/hr when the brakes are applied and the car is brought to a stop in 4.7 s. Find the magnitude of the force that stops the car, assuming it is constant.

**math**

While riding your motorcycle, you break to miss hitting a dog. your tires leave a skid mark as you come to a stop. the skid mark forms four angles when it crosses the painted line on the side of the road. one angle formed a 62 degree angle. what other angles are formed?

**chemistry**

At 20 °C, chloroform (CHCl3) has a density of 1.489 g/mL. What is the mass of 7.52 mL of chloroform at 20°C?

**chemistry**

When 15.5 + 0.125 + 2.55 are added, the answer with the correct number of significant figures is

**ANATOMY**

the three major vessels of the portal triad are the hepatic artery, hepatic portal vein and bile duct. What is the location of the triad relative to the liver lobules?

**science**

Circle the term that does not belong in each of the following groupings. 1. HC1 secretion Acetyicholine Histamine Secretin Gastrin 2. Gastric emptying Slowed by fats Enterogastric reflex Solid foods 3. Cephalic phase Reflex phase Intestinal phase Psychological stimuli 4. ...

**Physics**

A ball is thrown horizontally from the roof of a building 29.7 m high at 39.6 m/s. (a) What is the vertical velocity of the ball when it lands? (use down as the positive y-axis direction)b) What is the ball’s total velocity (speed and direction) when it lands?

**physics**

The lob in tennis is an effective tactic when your opponent is near the net. It consists of lofting the ball over his head, forcing him to move quickly away from the net (as shown in the figure below). Suppose that you loft the ball with an initial speed of v = 15.6 m/s, at an...

**chemistry**

What is the pH of a 2.8 M solution of HClO4?

**chemistry**

What is the pH of a 2.8 M solution of HClO4?

**chemistry**

i didn't know ph could be greater than 14 and poh less than 0

**chemistry**

A solution of NaOH(aq) contains 6.2 g of NaOH(s) per 100.0 mL of solution. Calculate the pH and the pOH of the solution at 25 °C.

**chemistry**

A solution of NaOH(aq) contains 6.2 g of NaOH(s) per 100.0 mL of solution. Calculate the pH and the pOH of the solution at 25 °C.

**science/anatomy**

common pathways for food and air are the (1), which connects to the mouth, and (2), which connects to the larynx. Epithelium in this region is (3), which provideds good protection from friction. Three bands of skeletal muscle, the (4) propel food into the (5). Entrance to the ...

**ENGLISH**

I have to write an essay about whether or not Jonathan Swift's "A Modest Proposal" was effective as a satire. one quote i have is "I have been assured by a very knowing American of my acquaintance in London, that a young healthy child well nursed, is, at a ...

**science**

how is eating breakfast important to prevent fainting

**SCIENCE**

what are the physiological benefits of eating breakfast. what are the physiological occurances or causes of fainting (syncope). how are these two ^ related and what is the significance

**ANATOMY**

what are the physiological benefits of eating breakfast. what are the physiological occurances or causes of fainting (syncope). how are these two ^ related and what is the significance

**math**

yo mama

**Math**

Please check- I got 10 4(9-2)/2^2+3

**MATH**

Look at this inequality 4m-9<2m-3 Solve the inequality for m. PLEASE HELP ME! CAN YOU PLEASE DO IT STEP BY STEP?

**algebra**

haaaa

**Business Statistics**

Instructions: Prepare your answers using Excel and show your work to get full or partial credit. Question 1: Using the file Wages.xlsx which contains information of working individuals, for a nationwide firm (Value 7 points). a) Run Descriptive Statistics for the variables ...

**College English**

How can I compare "Mother Night" by Vonnegut and "Song of Solomon" by Morrison in terms of Postmodernism?

**Statistics**

A shipment of portable radios contains 14 good radios and 3 defective ones. If two are randomly selected (without replacement) and tested, find the probability that at least one will be defective.

**Statistics**

A shipment of portable radios contains 14 good radios and 3 defective ones. If two are randomly selected (without replacement) and tested, find the probability that at least one will be defective.

**calculus II**

Do a u substitution. u= 1- sqrt(x) du = -(1/(2*sqrt(x)))dx Change your limits by plugging them into the u equation. u= 1 - sqrt(0) = 1-0 = 1 u= 1 - sqrt(9/16) = 1-(3/4) = 1/4 Substitute the u values in for x. The new integral is -2*sqrt(u) du from [1,1/4] OR 2*sqrt(u) du from...

**------college algebra division**

Whoops, some of it didn't line up, but I used the long division method

**------college algebra division**

5x^2 -3x -18 +((12x+71)/(x^2+4)) ___________________________ x^2 +4| 5x^4 -3x^3 +2x^2 +0x -1 -5x^4 -20x^2 --------------------------- -3x^3 -18x^2 +0x -1 +3x^2 +12x --------------------- -18x^2+12x -1 +18x^2 +72 --------------- 12x +71

**statistics**

The claim: mean < 900 other option: mean > or = 900 The null hypothesis is the one with an equal sign... Your null hypothesis would be mean=900 Your alt. hypothesis would be mean<900 The alt. hypothesis is the claim.

**history**

Levy's purpose in the film Crimes and Misdemeanors

**Math**

On a grid, an upright square is a square that is well, upright, on one of its sides, with the sides going along the grid points.

**Math**

I need help on this question, I know the answer (or, at least I think I know it), but I can't think of the rest. Bobby claims that only upright squares can have rational numbers for side lengths. Is he correct? Explain. I got yes, he is correct, but I can't hink of an ...

**Science**

Well, you can write down what your phenotypes are (how you look, ex: eye color, hair color, hair type, etc.) and then by using that, you canfigure out your genotypes by researching whether each of your traits are dominant or recessive. For example, I have a straight hairline, ...

**Chemistry**

Suppose 33.5 g of ClF3(g) and 29.1 g of Li(s) are mixed and allowed to react at atmospheric pressure and 25 C until one of the reactants is used up, producing LiCl(s) and LiF(s). Using the NIST value for the enthalpy of formation of ClF3 (webbook.nist.gov), calculate the ...

**Chemistry**

A 2.3 g sample of C5H10O is burned completely in excess oxygen to yield CO2(g) and H2O(l) at 25 C, releasing 83.42 kJ of energy. What is the enthalpy of formation of C5H10O?

**chemistry**

Calculate the volume of natural gas (methane) required to bring 2.6 L of water to a boil. Assume the initial temperature of the water is 21 C, and the methane is at 1 bar and 25 C. Assume that methane is an ideal gas, the specific heat capacity of water to be constant and ...

**Thermochemistry**

Hint: Write the balanced combustion reaction. You can find the standard enthalpies of formation for O2, CO2, and H2O from many sources, including the CRC Handbook of Chemistry and Physics. Solution: Balanced combustion reaction: C8H18 + 12.5 O2 --> 8 CO2 + 9 H2O From the ...

**Physics**

Pam has a mass of 44.0 kg and she is at rest on smooth, level, frictionless ice. Pam straps on a rocket pack. The rocket supplies a constant force for 22.0 m and Pam acquires a speed of 58.0 m/s.

**Science 7R (Lab questions)**

Animal cells lack in a cell wall. Plant cells have it.

**trig**

pi/3 is 7 square root 3/ 2 pi is - 7 square root 3 / 2 and 7pi/6 is -7

**trig**

i didn't realize it was just plugging in! thanks! i just need to figure out how to subtract fractions with pi in them now

**trig**

For the following expression, find the value of y that corresponds to each value of x, then write your results as ordered pairs (x,y). y=7cos(x-pi/6) for x=pi/6, pi/3, 2pi/3, pi, 7pi/6

**chemistry**

Which of the following sets of solute and solvents will make a homogeneous solution? (naphthalene is a non-polar organic molecule) 1. Water and benzene 2. Benzene and ammonium nitrate 3. Benzene and naphthalene 4. Water and naphthalene

**chemistry**

What is the molecular geometry for SH2? 1. Bent 2. Trigonal planar 3. Tetrahedral 4. Liner

**chemistry**

What volume of a 7.00 M solution of Ca(OH)2 is needed to neutralize 37.2 mL of a 3 M solution of nitric acid? 1. 15.9 mL 2. 37.2 mL 3. 7.97 mL 4. 24.2 mL

**chemistry**

What is the mass percent of a solution if 42.9 grams of aspirin is dissolved into 175 mL of ethanol? (Density of ethanol is 0.789 g/mL) 1. 31.1 % 2. 24.5 % 3. 23.7 % 4. 19.7 %