Mastering Moles Conversion

The number of atoms in a mole of ANY pure substance is equivalent to

• its atomic number

• its mass number

• 6.02 x 10²³

• Avogadro's constant

To determine the molar mass of an element, one must know the element's

• atomic number

• atomic mass

• number of isotopes

• Avogadro's constant

The Avogadro's number of atoms of any element is equivalent to

• the mass of that element

• the atomic number of that element

• 6.02 x 10²³ particles

• 100 g of that element

The atomic number of carbon is 6. The atomic number of fluorine is 9. Compared with a mole of carbon, a mole of fluorine contains

• 3 times as many atoms

• 1/3 as many atoms

• an equal number of atoms

The mass of 1 mol of chromium is about

• 52 g

• 24 g

• 12 g

• 6.02 x 10²³ g

A mass of 46 g of sodium contains about

• 46 mol of Na

• 23 mol of Na

• 2 mol of Na

• 1 mol of Na

The mass of 1.5 moles of cobalt is

• 59 g

• 64 g

• 88 g

• 118 g

How many moles are there in 9.03 x 10²³ atoms?(Hint: divide Avogadro's number to the given atoms)

• 1 mol

• 1.5 mol

• 15 mol

How many moles are there in 9.03 x 10²⁴ molecules of water?(Hint: divide Avogadro's number to the given molecules of water)

• 1 mol

• 1.5 mol

• 3 mol

• 15 mol

Tags

NGSS.HS-PS1-7

How many molecules are in 25 grams of NH₃? Put in order the steps below in solving this problem.

1. Multiply the mole by Avogadro's constant

2. calculate the molar mass of NH3

3. Divide the molar mass of NH3 by the given grams

4. Look for the atomic masses of all the elements in the molecules of NH3

• 1, 2, 3, 4

• 4, 2, 3, 1

• 4, 3, 2, 1

• 4, 3, 1, 2