Question

in the chemical equation: 2al + 3o2 → 2al2o3, how many oxygen atoms are present on the reactant side? there are 2 oxygen atoms on the reactant side of the equation. there are 3 oxygen atoms on the reactant side of the equation. there are 4 oxygen atoms on the reactant side of the equation. there are 6 oxygen atoms on the reactant side of the equation. how many hydrogen atoms are present in 4 molecules of methane (ch4)? there are 4 hydrogen atoms in 4 molecules of methane (ch4). there are 8 hydrogen atoms in 4 molecules of methane (ch4). there are 12 hydrogen atoms in 4 molecules of methane (ch4). there are 16 hydrogen atoms in 4 molecules of methane (ch4).

Explanation:

Step1: Analyze oxygen atoms in reactant

In the equation $2Al + 3O_2
ightarrow2Al_2O_3$, the reactant with oxygen is $O_2$. The coefficient of $O_2$ is 3, and each $O_2$ molecule has 2 oxygen - atoms.

Step2: Calculate number of oxygen atoms

The number of oxygen atoms is $3\times2 = 6$.

Step3: Analyze hydrogen atoms in methane

The chemical formula of methane is $CH_4$, which means each methane molecule has 4 hydrogen atoms.

Step4: Calculate number of hydrogen atoms in 4 methane molecules

If there are 4 molecules of methane, the number of hydrogen atoms is $4\times4=16$.

Answer:

For the number of oxygen atoms on the reactant side: There are 6 oxygen atoms on the reactant side of the equation.
For the number of hydrogen atoms in 4 molecules of methane: There are 16 hydrogen atoms in 4 molecules of methane (CH4).