When MgO and H2O react they form Magnesium Hydroxide Mg(OH)2
If uranium-241 lost 2 protons and 2 neutrons, then thorium-237 would be produced. The number beside the element is the mass number which is the sum of protons and neutrons. If uranium would lose 2 protons and 2 neutrons, then the mass number would decrease by 4 making it 237. Looking in a periodic table, thorium is the element which has a mass number of 237.
B is true because plants can only use nitrogen in the form of nitrates, no other living thing needs nitrogen therefore the percentage of nitrogen in the atmosphere is 79%
Answer is D. Both I and III are spontaneous graphs because the change in G < 0.