The answer is B I hope this helps you
Answer : The balanced redox reaction will be,

Explanation :
The given chemical equation is,

In the half reaction method, the number of atoms in each half reaction and number of electrons must be balanced.
The half reactions in the acidic medium are :
Reduction :
......(1)
Oxidation :
.......(2)
Now multiply the equation (2) by 4 and then added both equation, we get the balanced redox reaction.
Thus, the balanced redox reaction will be,

If you have a magnesium for every oxygen, then you have to start with two magnesiums. So the balanced equation is 2 Mg + O2 2 MgO.
And
CaCO3———→CaO + CO2
I hope it helped!
Explanation:
Nitric acid reacts with copper according to the reaction: ... 4 HNO3(l) + Cu(s) ==> Cu(NO3)2(s and aq) + 2 NO2(g) + 2 H2O(l) The copper nitrate salt that forms is a deep blue color. The nitrogen dioxide is a maroon vapor.
Answer:
CH
Explanation:
We have to obtain the mass of carbon and hydrogen in CO2 and H2O respectively.
For carbon in CO2;
0.845 * 12/44 = 0.23 g
For hydrogen in H20;
0.173 * 2/18 = 0.019 g
We convert the masses to moles of carbon and hydrogen
For carbon - 0.23/ 12 = 0.019 moles
For hydrogen - 0.019/1 = 0.019 moles
Dividing by 0.019 moles for carbon and hydrogen we have the emperical formula of the compound as CH