Question

question 4 (1 point)
masscalc2. determine how many grams of water will be produced when 4.0 g of hydrogen reacts with excess amount of oxygen according to the following reaction.
$2\\ h_2\\ +\\ o_2\\ \
ightarrow\\ 2\\ h_2o$
molar masses : $h_2$ : 2.02 g/mol $o_2$ : 32.(
18 g
9.0 g
72 g
36 g

Explanation:

Step1: Calculate moles of \( H_2 \)

Moles of \( H_2 = \frac{\text{mass of } H_2}{\text{molar mass of } H_2} = \frac{4.0\ g}{2.02\ g/mol} \approx 1.98\ mol \)

Step2: Relate moles of \( H_2 \) to \( H_2O \)

From the reaction \( 2H_2
ightarrow 2H_2O \), the mole ratio of \( H_2 \) to \( H_2O \) is \( 1:1 \). So moles of \( H_2O = 1.98\ mol \)

Step3: Calculate molar mass of \( H_2O \)

Molar mass of \( H_2O = 2(1.01) + 16.00 = 18.02\ g/mol \) (using \( H = 1.01\ g/mol \), \( O = 16.00\ g/mol \))

Step4: Calculate mass of \( H_2O \)

Mass of \( H_2O = \text{moles} \times \text{molar mass} = 1.98\ mol \times 18.02\ g/mol \approx 35.7\ g \), which is approximately \( 36\ g \)

Answer:

36 g (the option with 36 g)