Answer:
Explanation:
The second one is quite simple. CH4 (methane) is the main component for natural gas. It is used to heat houses in many many areas. It it heats a house, it must give off heat. It is exothermic.
The first one is much less common and hard to reason. I think it is easier to see the reverse reaction
O2 ===> 2O
O2 is a fairly stable molecule. It takes energy to break the molecules apart. That makes this reaction endothermic.
So the reaction you are given is just the opposite. It must be exothermic.
2O ===> O2 must be exothermic.
Answer:
30g
Explanation:
According to this question, a sulfur-containing compound is said to contain 15 percent by mass of sulfur. This means that 15% of the total mass of the compound is the mass of sulfur in the compound.
The question further states that there is a total of 200g of the compound containing sulfur, this means that the mass of sulfur can be calculated this:
Mass of sulfur = 15% of 200g
15/100 × 200g
15 × 2
30g
Hence, there are 30g of sulfur in 200g of the sulfur containing compound.
A heterogeneous mixture is one that is not evenly mixed
A homogeneous mixture is one that is evenly mixed
im pretty sure the answer you are looking for is relative though because mixtures do not have a fixed composition