Question

the mole and avogadros number
name
one mole of a substance contains avogadros number (6.02 x 10²³) of molecules.
how many molecules are in the quantities below?

1. 2.0 moles
2. 1.5 moles
3. 0.75 mole
4. 15 moles
5. 0.35 mole

Explanation:

For question 4 (15 moles):

Step1: Recall the formula

To find the number of molecules, we use the formula: Number of molecules = Moles × Avogadro's Number ($6.02\times10^{23}$ molecules/mole)

Step2: Substitute the values

Moles = 15, Avogadro's Number = $6.02\times10^{23}$
So, Number of molecules = $15\times6.02\times10^{23}$

Step3: Calculate the product

First, calculate $15\times6.02 = 90.3$
Then, multiply by $10^{23}$: $90.3\times10^{23}=9.03\times10^{24}$ (in scientific notation)

Step1: Recall the formula

Number of molecules = Moles × Avogadro's Number ($6.02\times10^{23}$ molecules/mole)

Step2: Substitute the values

Moles = 0.35, Avogadro's Number = $6.02\times10^{23}$
So, Number of molecules = $0.35\times6.02\times10^{23}$

Step3: Calculate the product

First, calculate $0.35\times6.02 = 2.107$
Then, multiply by $10^{23}$: $2.107\times10^{23}$

Answer:

The number of molecules in 15 moles is $9.03\times10^{24}$

For question 5 (0.35 mole):