Answer:
A. N₂(g) + 3H₂(g) -----> 2NH₃ exothermic
B. S(g) + O₂(g) --------> SO₂(g) exothermic
C. 2H₂O(g) --------> 2H₂(g) + O₂(g) endothermic
D. 2F(g) ---------> F₂(g) exothermic
Explanation:
The question says predict not calculate. So you have to use your chemistry knowledge, experience and intuition.
A. N₂(g) + 3H₂(g) -----> 2NH₃ is exothermic because the Haber process gives out energy
B. S(g) + O₂(g) --------> SO₂(g) is exothermic because it is a combustion. The majority, if not all, combustion give out energy.
C. 2H₂O(g) --------> 2H₂(g) + O₂(g) is endothermic because it is the reverse reaction of the combustion of hydrogen. If the reverse reaction is exothermic then the forward reaction is endothermic
D. 2F(g) ---------> F₂(g) is exothermic because the backward reaction is endothermic. Atomisation is always an endothermic reaction so the forward reaction is exothermic
Answer : The answer is,
Explanation :
Scientific notation : It is defined as the way or representation of expressing the number that are too big or too small that is written in the decimal form. That means always written in the power of 10 form.
For example : 8000 is written as,
in this notation, the significant figure is, 1 but
in this notation, the significant figures are, 2
The given problem are :

According to the divide and multiplication rules of scientific figures, the final answer is only as precise as the value with the least number of significant figures.
Hence, the answer is,
Answer:
B: The transport oxygen and nutrients around your body and help to get rid of wastes
Explanation:
The circulatory system carries oxygen and nutrients to the body, but it can also help get rid of waste (though that isn't a huge function of it).
Answer:
See Explanation and image attached
Explanation:
Methane is an alkane. The commonest chemical reaction that alkanes undergo is substitution. During a substitution reaction, one or more atoms of hydrogen is/are replaced in the alkane.
In methane, in the presence of sunlight and molecular chlorine gas, a homolytic fission of Cl2 occurs to yield chlorine radicals in an initiation step.
The propagation steps involve reaction of the methane with chlorine radicals. Certain intermediates continue to be formed along the way until the tetrachlorination product is finally obtained.