Question

Нагревают 29.2 г смеси СаСО3 и MgCO3. После полного разложения карбонатов до оксидов и углекислого газа получено 0.3 моля СО2. Определите, сколько молей СаСО3 и MgCO3 содержится в смеси.

Answer 1

CaCO3=CaO+CO2
MgCO3=MgO+CO2
Mr(CaCO3)=100
Mr(MgCO3)=24+12+48=84
обозначим количество карбоната кальция за х, а магния за у.
 составим систему уравнений:
х+у=0,3
х*М(CaCO3) + у*М(MgCO3) = 29,2
100x+84y=29.2
x+y=0.3
x=0.3-y
100(0.3-y)+84y=29.2
30-100y+84y=29.2
-16y= -0.8
y=1/16=0.05 моль CaCO3
x=0.3-0.05=0.25 моль MgCO3

Answer 2

Calculation of Moles of CaCO3 and MgCO3 in the Mixture

To determine the number of moles of CaCO3 and MgCO3 in the mixture, we can use the information provided about the complete decomposition of the carbonates and the amount of CO2 produced.

Given: - Mass of the mixture = 29.2 g - Moles of CO2 produced = 0.3 mol

We need to find the number of moles of CaCO3 and MgCO3 in the mixture.

Let's assume the moles of CaCO3 in the mixture is x, and the moles of MgCO3 in the mixture is y.

The molar mass of CaCO3 is 100.09 g/mol, and the molar mass of MgCO3 is 84.31 g/mol.

From the balanced chemical equation for the decomposition of carbonates, we know that 1 mole of CaCO3 produces 1 mole of CO2, and 1 mole of MgCO3 also produces 1 mole of CO2.

Therefore, we can set up the following equations:

x + y = 29.2 g (equation 1) x + y = 0.3 mol (equation 2)

To solve these equations, we can use substitution or elimination method.

Let's solve the equations using the elimination method:

Subtracting equation 2 from equation 1, we get:

29.2 g - 0.3 mol = 0

Since the units of grams and moles cannot be directly subtracted, we need to convert one of the units to match the other.

Using the molar mass of CaCO3 (100.09 g/mol), we can convert the grams to moles:

29.2 g * (1 mol / 100.09 g) = 0.2917 mol

Now, we can rewrite the equation as:

0.2917 mol - 0.3 mol = 0

Simplifying, we find:

-0.0083 mol = 0

This implies that the moles of CaCO3 and MgCO3 in the mixture are equal to 0.3 mol.

Therefore, there are 0.3 moles of CaCO3 and 0.3 moles of MgCO3 in the mixture.

Please note that the given information does not provide a direct way to determine the individual amounts of CaCO3 and MgCO3 in the mixture. The calculations above assume that the moles of CaCO3 and MgCO3 are equal.