Answer:
2Cu2S + 3O2 + 2C -------> 4Cu + 2SO2 + 2CO
Explanation:
Equation 1 should correctly be written as;
2Cu2S + 3O2-----> 2Cu2O + 2SO2
Equation 2 should be correctly written as;
2Cu2O + 2C -----> 4Cu + 2CO
The overall reaction equation is;
2Cu2S + 3O2 + 2C -------> 4Cu + 2SO2 + 2CO
Note that species that are intermediates are cancelled out .
Answer:
1.3 × 10³ cm³
Explanation:
The gas occupies a volume of V₁ = 310 cm³ under standard temperature and pressure (STP), that is, T₁ = 273.15 K and P₁ = 1.0 atm. In order to find the volume V₂ under different conditions we can use the combined gas law formula.

Answer:
A
C
A
Explanation:
Iam not sure if it's correct
Answer: The missing coefficient is 2.
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

As in the products, there are 2 atoms of sodium, thus there will be 2 atoms of of sodium in the reactant as well. This will balance the number of hydrogen and oxygen atoms as well.
Thus the missing coefficient is 2.
The total mass is 10.57+6.96=17.53 g.
So, the percent by mass of magnesium is (10.57)/(17.53) * 100 = <u>60.3%</u>
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The percent by mass of oxygen is (6.96)/(17.53) * 100 = <u>39.7%</u>