Mass number= atomic number + number of neutrons.
A=Z+N
Z=number of protons=12
N=12
A=12+12=24
If, we have 12 protons and 10 electrons, the charge of this ion is +2
Therefore: mass number:24; charge: +2
Answer: a. mass number: 24; charge: +2
A catalyst is a substance that increases the rate of a chemical reaction without itself being consumed . (ans: second choice)
Answer:
Therefore it will take 7.66 hours for 80% of the lead decay.
Explanation:
The differential equation for decay is
Integrating both sides
ln A= kt+c₁
[
]
The initial condition is A(0)= A₀,
.........(1)
Given that the 
has half life of 3.3 hours.
For half life 
putting this in equation (1)
[taking ln both sides, 
]
⇒k= - 0.21
Now A₀= 1 gram, 80%=0.8
and A= (1-0.8)A₀ = (0.2×1) gram = 0.2 gram
Now putting the value of k,A and A₀in the equation (1)
⇒ t≈7.66
Therefore it will take 7.66 hours for 80% of the lead decay.
Answer: [N2]₀ = 10M and [H2]₀ = 11M
Explanation: To calculate the initial concentration, you would have to set up an ICE table, which is an organized way of tracking known quantities or the ones you want to find. ICE stands for:
I is initial amount;
C is change in concentration;
E is for equilibrium concentration;
For the mixture,
N2 3H2 2NH3
I [N2]₀ [H2]₀ 0
C - x -3x +2x
E [N2]₀ - x =8 [H2]₀ - 3x =5 2x =4
With the product, we can find "x":
2x=4
x=2M
With x=2, find the concentrations:
[N2]₀ - x = 8
[N2]₀ = 10M
[H2]₀ - 3x = 5
[H2]₀ = 11M
The initial concentrations of nitrogen gas [N2] is 10.0 M and of hydrogen gas [H2] is 11.0 M.
The answer is C because it says describe the final sugar and C is unsaturated and in the problem it says as much as sugar will dissovle .
