Use equation
number of moles= sample mass/molar mass
Answer:
-2
Explanation:
7 x 1 - 2 x 1 + 1 x 1 + 3C = 0 (no charge)
6 + 3C = 0
C = -2
The concentration of the acid decreases
Answer: increases by
As a chlorine atom becomes a negative ion, the atom "increases by" an electron
Explanation:
Chlorine atom has an atomic number of 17, and an electronic configuration of 1s2, 2s2 2p6, 3s2 3p5 showing 7 valence electrons in its outermost shell.
Hence, it receives a single electron to achieve a stable octet structure with electronic configuration of
1s2, 2s2 2p6, 3s2 3p6. Therefore, Cl- is a univalent negative ion with 8 valence electrons in its outermost shell. The increase is shown below
Cl + e- --> Cl-
Thus, as a chlorine atom becomes a negative ion, the atom "increases by" an electron
<h3>
Answer:</h3>
6.25 atoms
<h3>
Explanation:</h3>
<u>We are given</u>;
- The half life of Po-218 is 3 minutes
- Initial sample is 200 atom
- Time of decay is 15 minutes
We are required to calculate the remaining mass after decay;
Half life refers to the time taken for original amount of a radioactive sample to decay to a half.
To calculate the remaining mass we use the formula;
N = N₀ × 0.5^n where n is the number of half lives, N is the new amount and N₀ is the original amount.
n = 15 min ÷ 3 min
= 5
Therefore;
New amount = 200 atom × 0.5^5
= 6.25 atoms
Therefore; the amount of the sample that will remain after 15 minutes is 6.25 atoms.
