Chapter 4, Problem 2ASA

If one can find the ratio of the number of moles of the elements in a compound to one another, one can find the formula of the compound. In a certain compound of copper and oxygen, ${\text{Cu}}_x{\text{O}}_y$, we find that a sample weighing $0.9573\text{g}$ contains $0.7649\text{g}\text{Cu}$.

a. How many moles of $\text{Cu}$ are there in the sample?

$\left(\text{Moles}\text{of}\text{Cu}=\frac{\text{mass}\text{of}\text{Cu}}{\text{molar}\text{mass}\text{of}\text{Cu}}\right)$

$\underset{\_}{}\text{moles}$

b. How many gram of $\text{O}$ are there in the sample? (The mass of the sample equals the mass of the $\text{Cu}$ plus the mass of $\text{O}$.)

$\underset{\_}{}\text{g}$

c. How many moles of $\text{O}$ are there in the sample.

$\underset{\_}{}\text{moles}$

d. What is the mole ratio $\left(\text{moles}\text{of}\text{Cu}/\text{moles}\text{of}\text{O}\right)$ in the sample?

$\underset{\_}{}:1$

e. What is the formula of the oxide? (The atom ratio equals the mole ratio and is expressed using the smallest integers possible.)

$\underset{\_}{}$

f. What is the molar mass of the copper oxide?

$\underset{\_}{}\text{g}/\text{mol}$