Answer: The ratio of carbon dioxide molecules to oxygen molecules is 20 :31
Explanation:
Combustion is a chemical reaction in which hydrocarbons are burnt in the presence of oxygen to give carbon dioxide and water.
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.
The balanced combustion reaction is,:

Thus the ratio of carbon dioxide molecules to oxygen molecules is 20 : 31
Explanation:
Sodium metal reacts rapidly with water to form a colourless basic solution of sodium hydroxide (NaOH) and hydrogen gas (H2). The reaction continues even when the solution becomes basic. The resulting solution is basic because of the dissolved hydroxide.
<span>El Niño during the time of 1997 to 1998 caused drought in Southeast Asia and flooding in much of Latin America and in the Horn of Africa due to significant amounts of rainfall. The effects in both places were numerous deaths. In areas where it flooded, mudslides occurred and spoiled seed stores. In areas of drought, crops were extremely diminished and let to starvation.</span>
Answer:
8.96 L
Explanation:
At STP, 1 mole = 22.4 L
0.400 mole * (22.4 L. /1 mole of gas) = 8.96 L
Answer:
Percent yield of SiC is 77.0%.
Explanation:
Balanced reaction: 
Molar mass of SiC = 40.11 g/mol
Molar mass of
= 60.08 g/mol
So, 100.0 kg of
=
moles of
= 1664 moles of 
According to balanced equation, 1 mol of
produces 1 mol of SiC
Therefore, 1664 moles of
produce 1664 moles of SiC
Mass of 1664 moles of SiC =
= 66743g = 66.74 kg (4 sig. fig.)
Percent yield of SiC = [(actual yield of SiC)/(theoretical yield of SiC)]
%
=
%
= 77.0%