How many moles of nickel(II) chloride are present in 2.87 grams of this compound? moles
The correct answer and explanation is:
Correct Answer:
0.0221 moles of nickel(II) chloride (NiCl₂)
Explanation:
To determine how many moles of nickel(II) chloride are present in 2.87 grams, start with the molar mass of the compound. The molar mass is calculated by adding together the atomic masses of each element in the formula NiCl₂.
- Nickel (Ni) has an atomic mass of approximately 58.69 g/mol
- Chlorine (Cl) has an atomic mass of approximately 35.45 g/mol
Since there are two chlorine atoms, the total contribution from chlorine is:
2 × 35.45 = 70.90 g/mol
Now, add the mass of nickel and chlorine together:
58.69 + 70.90 = 129.59 g/mol
This means one mole of nickel(II) chloride weighs 129.59 grams.
To find the number of moles in 2.87 grams, use the formula:
moles = mass / molar mass
moles = 2.87 g / 129.59 g/mol
moles ≈ 0.0221 mol
This calculation shows that 2.87 grams of nickel(II) chloride corresponds to approximately 0.0221 moles.
Understanding this process is important in chemistry because it helps convert between the mass of a substance and the amount in moles, which is essential for stoichiometry. The mole is a standard unit in chemistry that represents a specific number of particles, such as atoms, ions, or molecules. Knowing the number of moles allows one to understand how much of a substance is involved in a chemical reaction and to calculate the proportions of reactants and products accordingly. This forms the foundation of chemical equations, reaction yields, and the study of chemical behavior on a quantitative level.