Question

Which of the following correctly illustrates the conservation of mass for the reaction below?4Nals) + O2g) → 2Na2015)23.03 16, 160302. 124 g Nazo92031. 160302 103 Na209203 N. 16,0 302, 124 g Na209203 1.329202124 za2016 1603 62,39921520

Answer 1

The mass conservation law is defined as:

The law states that mass is neither created nor destroyed in chemical reactions.

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Step 1

The reaction must be written and balanced: 4Na(s) + O2(g) → 2Na2O(s)

Step 2

The molar masses for all species are needed:

1 mole Na = 23 g

1 mole O2 = 32 g

1 mole Na2O = 62 g

Step 3

According to the mass conservation law:

4Na(s) + O2(g) → 2Na2O(s)

4 x 23 g reacts with 32 g and produced 2 x 62 g,

Therefore, 92 g Na reacts with 32 g O2 and produced 124 g N2O

Answer: 92.0 Na, 32.0 g O2, 124 g N2O