You are given a 5M solution and you need to make the following dilutions: 1 M, 100 mM, and 25 mM.
4A. What is the dilution factor for each of these dilutions?
4B. If you need 5 mL of each of the diluted solutions, how much of the 5M stock would you use, and how much water would you add? Show your work.
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The Kc for the following reaction at 225 ∘C is 1.7×102.
3H2(g)+N2(g)⇌2NH3(g)
If the equilibrium mixture contains 0.22 M H2 and 0.017 M N2, what
is the molar concentration of NH3?
Express your answer to two significant figures and include the appropriate units.
Enter your answer using dimensions of chemical concentration.
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Among Gas Chromatography, NMR spectroscopy, and distillation, which is better at identifying the unknown solvents? Which is better at determining % composition? Explain your answers about why is one better than other two and why the other two is not good?
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A fajans titration of a 0.9628 g sample containing chloride required 31.32 ml of 0.1001 M AgNO3. Express the result of this analysis in terms of the percent AlCl3 (FW= 133.34) in the sample.
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5. In Procedure II of Part 2 of the lab you will add the correct ratio of water to ice so that the final temperature of the water in the calorimeter is 0°C. Suppose you do this and get the following data: Mass of ice 23.5 g Mass of water originally in the calorimeter 73.79 g Initial temperature of water 25°C Final temperature of water and melted ice 0°C Determine ?Hfusion of water given these data. ----->5.92 kJ/mol
6. Given that ?Hfusion of water = 6.0 kJ/mol, determine the percent error with these data
__________%
7. In Procedure I of Part 2 of the lab, you add ice to more water than the minimum required. Questions 7-10 address this portion of the lab. Which of the following best describes what is in the calorimeter when the system reaches equilibrium?
a. There is only water in the calorimeter and the water is greater than 0°C.
b. There is a mixture of water and ice in the calorimeter and the temperature of the system is less than 0°C.
c. There is a mixture of water and ice in the calorimeter and the temperature of the system is 0°C.
d. There is a mixture of water and ice in the calorimeter and the temperature of the system is greater than 0°C.
e. There is only water in the calorimeter and the water is 0°C.
f. There is only water in the calorimeter and the water is less than 0°C.
8. So, you take ice out of the freezer and add it to room temperature water in a calorimeter (more than enough to just melt the ice). We can determine the ?Hfusion of water by assuming we can account for all energy transfer and that “heat lost” is equal to “heat gained”. We can assume that “heat lost” is due to which of the following? Check all that apply. Select all that are True.
a. Raising the temperature of ice to 0°C.
b. Cooling the calorimeter.
c. Melting the ice.
d. Raising the temperature of the melted ice from 0°C to the final temperature.
e. Cooling the water originally in the calorimeter.
9. We can assume that “heat gained” is due to which of the following? Check all that apply. Select all that are True.
a. Melting the ice.
b. Raising the temperature of the melted ice from 0°C to the final temperature.
c. Cooling the calorimeter.
d. Raising the temperature of ice to 0°C.
e. Cooling the water originally in the calorimeter.
10. We will use 29.1 g of ice and add it to 128.04 g of water at 25°C. Let’s assume that the ice starts at 0°C (we will allow the ice to sit out for a bit of time and “dry it” so we will make this assumption). For this PreLab assignment, let’s also assume we have a perfect calorimeter (you will judge this assumption in Part 1 of the lab). So, we have “heat lost” = “heat gained” as Cooling the 128.04 g of water originally in the calorimeter from 25°C to the final temperature = melting the 29.1 g of ice + raising the temperature of 29.1 g of the melted ice from 0°C to the final temperature. Given that ?Hfusion of water = 6.0 kJ/mol, determine the theoretical final temperature of the water left in the calorimeter when the system reaches equilibrium._____ °C
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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.
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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.
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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?
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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?
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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?
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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
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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
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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?
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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
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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
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