Answer:
The formula of the compound formed by Iron (ii) ions and chromate ions is FeCrO₄
Explanation:
Iron (ii) ions, Fe²⁺ have a positive charge of +2. Chromate ions, CrO₄²⁻, on the other hand have a positive charge of -2. When iron (ii) ions and chromate ions combine two form a compound, each ion will contribute a mole of ion towards the formation of the compound. This is in line with the idea that a compound carries no charge. The positive charge (+2) of the iron (ii) ions are balanced by the negative charge of the chromate ions as shown mathematically as follows;
+2 + (-2) = 0; i.e. Fe²⁺ + CrO₄²⁻ = FeCrO₄
Therefore, the formula of the compound formed by Iron (ii) ions and chromate ions is FeCrO₄
Make sure you numbers with variable are on one side and the numbers
Answer is: <span>mass of calcium carbonate needed is 120 grams.
</span>Chemical reaction:
CaCO₃(s) → CaO(s) + CO₂(g)<span>.
</span>V(CO₂) = 27.0 L.
Vm = 22.4 L/mol.
n(CO₂) = V(CO₂) ÷ Vm.
n(CO₂) = 27 L ÷ 22.4 L/mol.
n(CO₂) = 1.2 mol.
From chemical reaction: n(CO₂) : n(CaCO₃) = 1 : 1.
m(CaCO₃) = 1.2 mol.
m(CaCO₃) = n(CaCO₃) · M(CaCO₃).
m(CaCO₃) = 1.2 mol · 100 g/mol.
m(CaCO₃) = 120 g.
Answer:
a) CaF₂.
b) 7.81g of CaF₂ are present.
Explanation:
a) The calcium ion has as charge Ca²⁺ and fluoride ion is F⁻, that means formula unit is:
CaF₂
b) 1 molecule of CaF₂ contains 2 anions, F⁻. Thus, the moles of CaF₂ is:
1.2x10²³ anions * (1 moleculeCaF₂ / 2 anions) = 6x10²² molecules of CaF₂
6.022x10²³ molecules = 1mol:
6x10²² molecules of CaF₂ * (1mol / 6.022x10²³molecules) = 0.10 moles CaF₂.
1 mole of CaF₂ has a mass of 78.07g:
0.10 moles CaF₂ * (78.07g / mol) =
7.81g of CaF₂ are present
