A scientist wants to make a solution of tribasic sodium phosphate, Na3PO4, for a laboratory experiment. How many grams of Na3PO4 will be needed to produce 550. mL of a solution that has a concentration of Na+ ions of 0.800 M ?

Express your answer to three significant figures and include the appropriate units.

Part A:

How much work (in J) is required to expand the volume of a pump from 0.0 L to 2.8 L against an external pressure of 1.2 atm ?

Express your answer using two significant figures.

W =

Part B:

What is the mass of the silver block?

Express your answer to two significant figures and include the appropriate units.

A silver block, initially at 55.6 ∘C, is submerged into 100.0 g of water at 24.2 ∘C, in an insulated container. The final temperature of the mixture upon reaching thermal equilibrium is 26.9 ∘C.

How many liters of H2 at STP can be produced from the electrolysis of aqueous NaCl using a current of 50.0 mA for 1.0 hour?

Justify the following with clear hand writing and details: I'll be thankful.

- What is the mole fraction of HCl in a 36% by weight aqueous solution of HCl?

- A solution contains 4.00 g NaOH, 5.61 g KOH, and 1.03 g RbOH in 90.0 g of water. The solution’s density is 1.08 g/mL. What is the molality of OH– ?

- Why does a can of soda fizz when it is opened?

- Adding NaCl to water results in a solution with greater electrical conductivity than pure water.

a. If you add NaCl to oil, do you expect the electrical conductivity of the oil to increase? Why or why not?

b. Is solid NaCl a good conductor of electricity? Why or why not?

A 76.00-pound flask of mercury cost $146.00. The density of mercury is 13.534 g/cm^3.

A) Find the price of one cubic inch of mercury by calculating the following intermediate values.

What is the price of one pound of mercury? What is the price of one gram of mercury? What is the price of one cubic centimeter of mercury? What is the price of one cubic inch of mercury?

Which of the following set of quantum numbers (ordered n, ℓ, mℓ, ms) are possible for an electron in an atom? Check all that apply. Check all that apply.

5, 3, 0, 1/2

-3, 2, 2, -1/2

4, 2, -1, -1/2

3, 1, -2, -1/2

5, 3, 4, 1/2

2, 1, 0, 1

2, 4, 1, -1/2

5, 3, -3, 1/2

At a certain temperature, the equilibrium constant Kc for this reaction is 53.3

H2 + I2 ---> 2HI
<---
at this temperature, 0.500 mol of H2 AND 0.500 mol of I2 were placed in 1.00L container to react. What concentration of HI is present at equilibrium?

[HI]= ?M

If the surface area of the Pacific Ocean is 1.6176 x 10^8 km^2 and the average depth is 4,080 meters, how many moles of water in the Pacific?

in this example, 2.5 mol of an ideal gas with CV,m= 12.47Jmol-1K-1 is expanded adiabatically against a constant external pressure of 1 bar. The initial temperature and pressure of the gas are 325 K and 2.5bar respectively. The final pressure is 1.25 bar. Calculate the final temperature, q, w, ΔU and ΔH

Calculate the pH for each of the following cases in the titration of 25.0 mL of 0.150 M pyridine, C5H5N(aq) with 0.150 M HBr(aq): (a) before addition of any HBr (b) after addition of 12.5 mL of HBr (c) after addition of 14.0 mL of HBr (d) after addition of 25.0 mL of HBr (e) after addition of 30.0 mL of HBr

Calculate theoretical yield, actual yield and percent yield.

Data:
mass recovered: 12.1188 g.

2-methylcyclohexanol
MM: 114.2 g/mol
D: 0.930 g/mL
BP: 166 C

1-methylcyclohexene
MM: 96.2 g/mol
D:0.813 g/mL
BP: 110 C

Using molecular deuterium in the presence of the metal catalyst palladium hydrogenate this alkene: 2,3-dimethylbut-1-ene

1)Calculate the pH during the titration of 20.00 mL of 0.1000 M HF(aq) with 0.2000 M LiOH(aq) after 4 mL of the base have been added. K_a of HF = 7.4 x 10^-4.

2)Calculate the pH during the titration of 20.00 mL of 0.1000 M morphine(aq) with 0.100 M HCl(aq) after 10 mL of the acid have been added. K_b of morphine = 1.6 x 10^-6

Thank you.

I have ONE question for homework that is separated into different parts.

1)

a) Assume that the kinetic energy of a 1300 kg car moving at 120 km/h could be converted entirely into heat.

What amount of water could be heated from 21 ∘C to 51 ∘C by the car's energy?

b) Regarding the water in the car how much heat (in kilojoules) is evolved or absorbed in the reaction of 2.50 g of Na with H2O?
2Na(s)+2H2O(l)→2NaOH(aq)+H2(g) ΔH∘ = -368.4kJ.

c) Instant cold packs used to treat a person injured in a car accident contain solid NH4NO3 and a pouch of water. When the pack is squeezed, the pouch breaks and the solid dissolves, lowering the temperature because of the endothermic reaction
NH4NO3(s)+H2O(l)→NH4NO3(aq) ΔH= +25.7 kJ.

What is the final temperature in a squeezed cold pack that contains 44.0 g of NH4NO3 dissolved in 125 mL of water on a person who suffered a car accident? Assume a specific heat of 4.18J/(g⋅∘C) for the solution, an initial temperature of 26.0 ∘C, and no heat transfer between the cold pack and the environment.

d)Calculate ΔH∘f (in kilojoules per mole) for benzene, C6H6,(a chemical commonly used by cars) from the following data:
2C6H6(l)+15O2(g)→12CO2(g)+6H2O(l) ΔH∘ = -6534kJ
ΔH∘f (CO2) = -393.5kJ/mol
ΔH∘f (H2O) = - 285.8kJ/mol

e) For the reaction, 2 NH₃(g) → N₂(g) + 3 H₂(g), one would expect

1) ΔH° to be negative and ΔS° to be negative or 2) ΔH° to be positvie and ΔS° to be positive.