V solution (CaCl2) = 400 ml = 0.4 l
Cn (CaCl2) = 0.5 n
m (CaCO3) -?
1) Write the equation of a chemical reaction:
CaCl2 + Na2CO3 => CaCO3 ↓ + 2NaCl;
2) Calculate the amount of CaCl2:
n (CaCl2) = CH (CaCl2) * V solution (CaCl2) / z = 0.5 * 0.4 / 2 = 0.1 mol;
3) Determine the amount of CaCO3 substance (taking into account the coefficients in the reaction equation):
n (CaCO3) = n (CaCl2) = 0.1 mol;
4) Calculate the mass of CaCO3:
m (CaCO3) = n (CaCO3) * M (CaCO3) = 0.1 * 100 = 10 g.
Answer: The mass of CaCO3 is 10 g.
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