Answer:
Explanation:
We are asked to convert 1.45 moles of potassium hydroxide (KOH) to grams.
<h3>1. Molar Mass</h3>
The molar mass is the mass in grams of 1 mole of a substance. The values are found on the Periodic Table. They are the same as the atomic masses but the units are grams per mole (g/mol) instead of atomic mass units (amu).
We have the compound KOH. Look up the molar masses of the individual elements.
- Potassium (K): 39.098 g/mol
- Oxygen (O): 15.999 g/mol
- Hydrogen (H): 1.008 g/mol
The formula for the compound has no subscripts, so there is 1 mole of each element in 1 mole of the compound. We can simply add the molar masses.
- KOH: 39.098 + 15.999 + 1.008 =56.105 g/mol
<h3>2. Convert Moles to Grams</h3>
Based on the molar mass, there are 56.105 grams of KOH in 1 mole. Create a ratio using this information.
We are converting 1.45 moles of KOH to grams, so we multiply by this value.
The units of moles of KOH cancel.
<h3>3. Round </h3>
The original measurement of moles has 3 significant figures, so our answer must have the same.
For the number we calculated, that is the tenths place. The 5 in the hundredths place (81.3<u>5</u>225) tells us to round the 3 up to a 4.
<u>Approximately 81.4 grams of potassium hydroxide </u>are represented by 1.45 moles.