Question

1. how many atoms are there in 0.55 moles of argon (ar)?

a. 3.31x10²³
b. 3.65x10⁻²³
c. 6.022x10²³
d. 3.31x10²²
e. 2.40x10²⁵

Explanation:

Step1: Use Avogadro's number formula

Recall that number of atoms = moles × Avogadro's number, where Avogadro's number is $6.022 \times 10^{23}\ \text{atoms/mol}$.
Expression: $\text{Number of atoms} = 0.55\ \text{mol} \times 6.022 \times 10^{23}\ \text{atoms/mol}$

Step2: Calculate the product

Multiply the given values to find the total number of atoms.
Expression: $0.55 \times 6.022 \times 10^{23} = 3.3121 \times 10^{23} \approx 3.31 \times 10^{23}$

Atomic masses (approximate): Chlorine (Cl) = 35.45 amu, Helium (He) = 4.00 amu. Chlorine has a significantly larger atomic mass than Helium.

Answer:

a. $3.31 \times 10^{23}$

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For the second question (identifying the element with the largest atomic mass):