Heat energy because combustion is an exothermic reaction.
Some rocks contain carbonate minerals, and the acid test can be used to help identify them.
Density = mass / volume
1.5 = m / 50.0
m = 1.5 x 50.0
m = 75 g
hope this helps!
First, we write out a balanced equation.
HA <--> H(+) + A(-)
Next, we create an ICE table
HA <--> H+ + A-
[]i 0.40M 0M 0M
Δ[] -x +x +x
[]f 0.40-x x x
Next, we write out the Ka expression.
Ka = [H+][A-]/[HA]
Ka = x*x/(0.40-x)
However, because Ka is less than 10^-3, we can assume the amount of dissociation is negligible. Thus,
Assume 0.40-x ≈ 0.40
Therefore, 1.2x10^-6 = x^2/0.40
Then we solve for the [H+] concentration, or x

x=6.93x10^-4
Next, to find pH we do
pH = -log[H+]
pH = -log[6.93x10^-4]
pH = 3.2
Heat of Fusion is defined as the energy required to turn a liquid into a solid, or said phase changing latent heat. In this case the only choice that represents that phase change is (1). Where the heat removed to turn a liquid of a substance into it's solid form is instead added to excite the bonds and liquify it. Yet, heat of fusion (s) ->(l)
is still the same as going from liquid to solid just one is adding and the other is removing, respectively.