Question

1. calculate the percent composition of a compound composed of sulfur and oxygen where the compound weighs 45.6 g, and contains 17.6 grams of sulfur.

a. 72.1% s, 27.8% o
b. 38.6% s, 61.4% o
c. 54.7% s, 23.3% o
d. 74.3% s, 24.0% o

1. how many liters are needed to prepare a 5m solution with 7.5 moles solute? (l = m x moles)

a. 1.5 l
b. 37.5 l
c. 2.5 l
d. 15 l

1. you are asked to prepare a 10 l solution of 5m nacl. how many grams of salt will you need? (moles = m x l)

a. 2920 g nacl
b. 0.855 g nacl
c. 116.88 g nacl
d. 0.5 g nacl

1. dilution: you are given 0.250 liters of 1.88 m hno₃. you are asked to dilute the solution to a concentration of 0.125m. how many liters will the final solution be?

a. 0.47 l
b. 0.0588 l
c. 0.266 l
d. 3.76 l

1. convert the molecular formula of glucose (c₆h₁₂o₆), to the empirical formula.

a. c₁₂h₂₄o₁₂
b. c₀.₅ho₀.₅
c. c₃h₄o₃
d. ch₂o

1. molarity is a measure of:

a. volume
b. mass
c. density
d. concentration

1. calculate the percent composition of a compound that contains 15.7 g oxygen and 24.5 grams carbon. (2 points)

a. 64.1% o, 15.6% c
b. 39.1% o, 60.9% c
c. 15.3% o, 27.7% c
d. 56.1% o, 35.9% c

Explanation:

Step1: Calculate the mass of the compound

The mass of the compound is \(15.7 + 24.5=40.2\) g.

Step2: Calculate the percentage of oxygen

The percentage of oxygen is \(\frac{15.7}{40.2}\times100\approx39.1\%\)

Step3: Calculate the percentage of carbon

The percentage of carbon is \(\frac{24.5}{40.2}\times100\approx60.9\%\)

Answer:

B. \(39.1\%\ O, 60.9\%\ C\)