A, radium-228. Alpha radiation is essentially just two protons and two neutrons leaving the atom, causing the atomic number to drop by two (since the protons left) and the mass number to drop by four (since two neutrons and protons left).
The percent by mass sugar of a solution : 11.07%
<h3>Further explanation</h3>
Given
mass of sugar = 12.45 g
mass of water = 100 g
Required
The percent by mass
Solution
Mass of solution :
Percent mass of sugar :
Answer:
41.9 g
Explanation:
We can calculate the heat released by the water and the heat absorbed by the steel rod using the following expression.
Q = c × m × ΔT
where,
c: specific heat capacity
m: mass
ΔT: change in temperature
If we consider the density of water is 1.00 g/mol, the mass of water is 125 g.
According to the law of conservation of energy, the sum of the heat released by the water (Qw) and the heat absorbed by the steel (Qs) is zero.
Qw + Qs = 0
Qw = -Qs
cw × mw × ΔTw = -cs × ms × ΔTs
(4.18 J/g.°C) × 125 g × (21.30°C-22.00°C) = -(0.452J/g.°C) × ms × (21.30°C-2.00°C)
ms = 41.9 g
