Answer:
(1) Z = 82, M = 208; (2) Z = 82, M = 208
Step-by-step explanation:
(1) Decay of Th-232
The unbalanced nuclear equation is
The main point to remember in balancing nuclear equations is that the <em>sums of the superscripts and the subscripts must be the same on each side</em> of the equation.
Then
90 = x + 6×2 + 4(-1), so x = 90 – 12 + 4 = 82
232 = y + 6×4 + 4×0, so y = 232 – 24 = 208
Z = 82, M = 208
(2) Decay of U-238
The unbalanced nuclear equation is
Then
92 = x + 6×2 + 2(-1), so x = 92 – 12 + 2 = 82
238 = y + 6×4 +4×0, so y = 238 – 24 = 214
Z = 82, M = 214
Answer : B 3Mg + 2AlCl3 - 2Al + 3MgCl2
Explanation:
Reactants side Products side
Mg - 3 Mg - 3
Al - 2. Al - 2
Cl - 6 Cl - 6
The answer to this question would be: 2 half-lives
In this question, the mineral has a daughter to parent ratio of 3:1. That means, the amount of parent mass should be are 1/(3+1)= 1/4 of the total mass. For every half live, the parent mass would become 1/2. Then for 1/4, the number of half-lives should be:
1/2^x= 1/4
1/2^x= 1/2^2
x=2