Question

A chemist determines by measurements That 0.0300 moles of hydrogen gas participate in a chemical reaction. Calculate the mass of hydrogen gas that participates. Be sure your answer has the correct significant digits

Answer 1

We know that 0.0300 moles of hydrogen participate in a chemical reaction and we must calculate the mass

In order to calculate the mass we must use the next formula

$\text{ mass}=\text{ molar mass}\cdot\text{ number of moles}$

In this case, the number of moles is given, 0.0300 moles and the molar mass of the hydrogen is 1.00784 g/mol

Now, we must replace the values in the formula

$\text{ mass}=1.00784\frac{g}{mol}\cdot0.0300mol$

Finally, we must simplify the equation

$\text{ mass}=0.0302352g$

Using the correct significant digits,

$\text{ mass}=3.02\cdot10^{-2}g$

ANSWER:

$3.02\cdot10^{-2}$