<u>Answer:</u> The true statements are
for an endothermic reaction is positive, a combustion reaction is exothermic and when energy is transferred as heat from the system to the surroundings,
is negative.
<u>Explanation:</u>
There are 2 types of chemical reactions categorized into heat change:
- <u>Endothermic reactions:</u> These reactions are defined as the reactions in which energy is absorbed by the system from the surroundings. The
for these reactions is always positive. For Example: Changing of water into water vapor. - <u>Exothermic reactions:</u> These reactions are defined as the reactions in which energy is released by the system to the surroundings. The
for these reactions is always negative. For Example: Combustion reactions.
Combustion reactions are defined as the reactions in which a hydrocarbon reacts with oxygen gas to produce carbon dioxide and water. Heat is released during these reactions. Thus, it is considered as exothermic reactions.
Hence, the true statements are
for an endothermic reaction is positive, a combustion reaction is exothermic and when energy is transferred as heat from the system to the surroundings,
is negative.
False. They usually give away their electrons to form ionic bonds
When the solutions are diluted in half:
So [ Ca+2] = 0.001/2 = 0.0005 M
[SO4-2]= 0.01/2 =0.005
when Q = [Ca2+][SO4-2]
so by substitution:
Q = 0.0005*0.005 = 2.5x10^-6
by comparing with Ksp value
So when Q < Ksp
∴ the answer is no precipitation will occur, as the solution is unsaturated.
<span>False, because the only element with the highest Electronegativity is hydrogen and the atomic number is 1. hope this helps you :)</span>