In the reaction C + O2 → CO2, 18 g of carbon react with oxygen to produce 72 g of carbon dioxide. What mass of oxygen would be needed in the reaction?

Question

18 g
54 g
72 g
90 g

Answer 1

To determine the mass of oxygen needed in the reaction, we can use the principle of conservation of mass.

From the reaction \( C + O_2 \rightarrow CO_2 \):

1. Identify the masses:

   • Mass of carbon (C) = 18 g
   • Mass of carbon dioxide (CO2) produced = 72 g

2. Use the conservation of mass: The total mass of the reactants (C and O2) must equal the total mass of the products (CO2): \[ \text{Mass of reactants} = \text{Mass of products} \] \[ \text{Mass of C} + \text{Mass of O2} = \text{Mass of CO2} \] \[ 18,g + \text{Mass of O2} = 72,g \]

3. Rearrange to find the mass of O2: \[ \text{Mass of O2} = 72,g - 18,g = 54,g \]

Thus, the mass of oxygen needed in the reaction is 54 g.