$2 Ca+O_2 \rightarrow 2 CaO$
The molar mass of each substance is provided in the table below.
| Substance | Molar Mass (g/mol) |
| :-------- | :----------------- |
| Calcium $( Ca )$ | 40.08 |
| Oxygen $\left( O _2\right)$ | 32.00 |
| Calcium oxide $( CaO )$ | 56.08 |
What mass of calcium is needed?
$4.25 mol O _2$ $\square$
2 $\square$ mol Ca
40.1
g Ca
$=$ $\square$ g Ca
1
$mol O _2$
1
mol Ca
Answer (1)
To determine the mass of calcium needed in the reaction given, we can follow these steps:
Understand the Chemical Reaction :
The balanced chemical equation is:
2 Ca + O 2 → 2 CaO
This tells us that 2 moles of calcium (Ca) react with 1 mole of oxygen ( O 2 ) to produce 2 moles of calcium oxide (CaO).
Identify the Known and Unknown Values :
We know that we have 4.25 moles of O 2 .
We want to find the mass of calcium (Ca) required.
Use Stoichiometry :
According to the chemical equation, 1 mole of O 2 requires 2 moles of calcium (Ca). Therefore, 4.25 moles of O 2 will require:
4.25 moles O 2 × 1 mole O 2 2 moles Ca = 8.5 moles Ca
Calculate the Mass of Calcium Needed :
The molar mass of calcium (Ca) is 40.08 g/mol. To find the mass in grams for 8.5 moles of calcium:
8.5 moles Ca × 40.08 mol g = 340.68 g Ca
Therefore, you need 340.68 grams of calcium to react with 4.25 moles of oxygen.
Conclusion :
The mass of calcium needed for this reaction is 340.68 grams.
