Question

Your silver watchband has a mass of 326 g. How many moles of Ag do you have?

Answer 1

3.02 moles

Step-by-step explanation:

Converted using mole calculator.

Answer 2

`\boxed {\boxed {\sf 3.02 \ mol \ Ag}}`

Step-by-step explanation:

We want to convert grams of silver to moles of silver. We can do this in 2 steps.

1. Convert Grams to Moles

We can convert grams to moles using the molar mass. It tells us the mass of 1 mole of a substance.

This is a value found on the Periodic Table. It is the same value as the atomic mass, but the units are grams per mole (g/mol) instead of atomic mass units (amu). Look up silver's molar mass.

• Ag: 107.868 g/mol

Let's make a ratio using the molar mass.

`(107.868 \ g\ Ag)/( 1 \ mol \ Ag)`

Since we are converting 326 grams to moles, we multiply by that value.

`326 \ g\ Ag*(107.868 \ g\ Ag)/( 1 \ mol \ Ag)`

Flip the ratio so the units of grams of silver cancel.

`326 \ g\ Ag*( 1 \ mol \ Ag)/(107.868 \ g\ Ag)`

`326*( 1 \ mol \ Ag)/(107.868)`

`( 326)/(107.868) \ mol \ Ag`

`3.02221233359 \ mol \ Ag`

2. Round

The original measurement of mass (326 grams) has 3 significant figures, so our answer must have the same.

For the number we found, that is the hundredth place. The 2 in the thousandth place (3.02221233359) tells us to leave the 2 in the hundredth place.

`3.02 \ mol \ Ag`

A silver watchband with a mass of 326 grams is equal to 3.02 moles of silver.