Question

The element platinum is commonly used as a catalyst to accelerate the rates of chemical reactions. How many atoms of platinum (Pt) are present in 85.50 grams of platinum? Report your answer to 3 significant figures.

Answer 1

Question #72499, Chemistry / Other / Completed

The element platinum is commonly used as a catalyst to accelerate the rates of chemical reactions. How many atoms of platinum (Pt) are present in 85.50 grams of platinum? Report your answer to 3 significant figures.

Solution

The atomic weight of platinum is 195.084 [1]

$$N = v \cdot N_A - \text{is a formula for calculations}$$ $$N_A - \text{Avogadro constant, } 6.022 \times 10^{23} \text{ mol}^{-1}$$ $$v = m / M = 85.50 \text{ g} / 195.084 \text{ g/mol} = 0.43827 \text{ mol}$$ $$\text{So } N = 0.43827 \text{ mol} \cdot 6.022 \times 10^{23} \text{ mol}^{-1} = 2.64 \times 10^{23} \text{ atoms}$$

Answer: $2.64 \times 10^{23}$ atoms.

1. https://en.wikipedia.org/wiki/Platinum