Chemistry Answers

4.67g of solid silver nitrate are mixed into a 200.0mL solution of 0.500mol/L aqueous potassium sulfate. 

1. Calculate the moles of each reactant 

2. Identify which reactant is the limiting reactant

3. Calculate the moles of each product 

4. Calculate the theoretical yield of solid precipitate 

5. Assuming you get 3.88g of solid precipitate, calculate the percent yield 

To keep homemade ice cream frozen, it is placed in a bucket of ice-water and salt mixture. A mixture is commonly composed of 1.90 kg of salt (NaCl) and 7.25 kg of ice.

Problem: Calculate the mole fraction of NaCl in the mixture until the ice melts.

Lean meat is marinated and added moisture through brining. In brining, a mixture of salt and water is used to soak the meat for a few hours or days before cooking.

Basic Brine: Make 3880 grams brine for 2.72 kg of meat

Procedure:

a. Mix 250 grams of salt (NaCl) with 3880 grams of water.

b. If you make sweet brine, mix 250 grams of sugar (C12H22O11) to solution of salt and water.

Problem: What is the molal concentration of the brine solution (250 g salt + 3880 g water)?

How many number is bonds are in allenne

A lagoon has a volume of 1200 m3 and the flow into the lagoon is 2.5 m3/h. What is the rentention time in this lagoon?

One gram of pepper is placed into a 100-mL beaker, and the beaker is filled with water to the 100-mL mark. What is the concentration of pepper in mg/L?

62. Methylbenzene (toluene), CHI;CH;(1), is a common

paint thinner. It can be prepared from benzene, Cattal

CH,CI(g) + CoHo(1) > CH;CH;() + HCK(g)

In an investigation, 25.0 g of benzene is combined

with 20.0 g of chloromethane, CH, C1, in the presence

of an appropriate catalyst. (7.4, 7.5)

(a) Calculate the theoretical yield of toluene.

(b) If 22.0 g of CH, CH, is actually obtained, what is the

percentage yield?

(c)

Suggest reasons for the discrepancy between the

actual yield and the theoretical yield.

Suppose that 181.1 J of heat energy is required to completely vaporize 3.9 g of a pure liquid. If the molar mass of the liquid is 128.34 g/mol, what is the molar enthalpy of vaporization of the liquid?

4. What is the purpose of adjusting the polarity?

5. Would benzoic acid dissolve better in water, or in ethanol? Explain why using the concepts discussed in this laboratory.

In a final very careful and correct recrystallization from acetone, benzoic acid (pure mp 122-122.3°C) was melted on a melting point machine immediately after vacuum filtration and washing, and found to have a melting point of 116-121°C. Why is the melting point not

122-122.3°C? Assume that there are no solid compounds present other than benzoic acid present, and suggest what may be present to affect melting point, and what role that presence does.

2. What are 2 advantages of using gravity filtration over vacuum filtration when removing a solid impurity from a hot mixture?

3. If iron filings were an impurity present along with the ASA in this experiment, at which point in the recrystallization procedure would they be removed completely from the ASA? (What slide numbers show this procedure?)