False. The element abundant in our body is oxygen and on earth, it is still oxygen. The body is more than 50% water. A water molecule is 11% hydrogen and the rest is oxygen. That is why you can expect oxygen to be abundant in the body. Same is true with the earth. Majority of the oxygen is from the bodies of water the earth is rich of.
Answer:
The answer would be meniscus.
The elements that compose it and the arrangement of its atoms.
Answer: bạn viết phương trình Phenol + NaOH
=> nNaOH = nPhenol = 0,2 mol
m Phenol = 0,2x94 = 18,8 gam
%mPhenol = 18,8/28,9% = 65,05
Explanation:
Explanation:
a) H2S (aq) + 2 O2 (g) → H2SO4(aq)
b) H2SO4 (aq) + CaCO3(s) → CaSO4 (s) + H2O (L) +CO2 (g)
To identify a redox reaction, we have to monitor the oxidation number of the elements to see if there is change.
In reaction (a);
The oxidation number of S increases from -2 (H2S) to + 6 (H2SO4). Also the oxidation number of O decreases from 0 (O2) to -2 (H2SO4). This is a redox reaction.
The oxidizing agent is O2 because it was reduced and the reducing agest is H2S.
In reaction (b);
There is no change in oxidation number in any f the elements. This is not a redox reaction.
