Question

Twenty-four grams of magnesium metal reacts with sixteen grams of oxygen gas to form magnesium oxide. According to the law of conservation of mass, how much magnesium oxide will there be after the chemical change is complete?
24 g
30 g
40 g
16 g

Answer 1

hi,
Do u know the balance equation for this reaction ?

Answer 2

no

Answer 3

please help

Answer 4

It's
2Mg + O2 = 2MgO
Now wt is the piece of information u can get from this equation ...?

Answer 5

According to the balance equation....
2moles of Mg will react with 1mole of Oxygen gas to produce 2moles og MgO

Did u get it up to now ?

Answer 6

no it was 40g

Answer 7

1 mole of MgO = 24g
1 mole of O2 = 32g
1 mole of MgO = 40g

so we can say.....
2 mole of Mg + 1 mole ofO2 ----> 2mole of MgO
in this way..
48g of Mg + 32g of O2 ---> 80g of MgO -----(1)

but in the question.... they say
24g of Mg + 16g of O2......
to find the outcome when we use the above masses just divide (1) /2

which is
24g of Mg + 16g of O2 ----> 40g of MgO

so ya will get 40g of MgO

hope this will help ya !