Phase change is the solute
the one that doesn't phase change is the solvent.
A
Explanation:
Reaction equation showing alpha decay in Uranium-238 is as follows.

It is known that an alpha particle is basically a helium nucleus and it contains 2 protons and 2 neutrons.
Symbol of an alpha particle is
.
As atomic mass or weight is the sum of total number of protons and neutrons present in an atom.
Hence, the atomic weight of the alpha particle is (2 + 2) = 4.
Atomic mass W = 183.84 u.m.a
1 mole --------- 183.84
1.4 moles ---- ?
1.4 x 183.84 / 1 = 257.376 g
hope this helps!
Answer:
Qm = -55.8Kj/mole
Explanation:
NaOH(aq) + HNO₃(aq) => NaNO₃(aq) + H₂O(l)
Qm = (mc∆T)water /moles acid
Given => 100ml(0.300M) NaOH(aq) + 100ml(0.300M)HNO₃(aq)
=> 0.03mole NaOH(aq) + 0.03mole HNO₃(aq)
=> 0.03mole NaNO₃(aq) + 0.03mole H₂O(l)
ΔH⁰rxn = [(200ml)(1.00cal/g∙°C)(37 – 35)°C]water / 0.03mole HNO₃
= 13,333 cal/mole x 4.184J/cal = 55,787J/mol = 55.8Kj/mole (exothermic)*
Heat of reactions comes from formation of H-Oxy bonds on formation of water of reaction and heats the 200ml of solvent water from 35⁰C to 37⁰C.