Answer:
When there remains one-quarter of the sample, the age of the sample is 10940 years
Explanation:
<u>Step 1:</u> Data given
The half-life of C-14 is 5470 years.
The half- life time is the time required for a quantity to reduce to half of its initial value.
This means after 5470 years there remains half of the C-14 sample.
To remain a quarter of the sample, another cycle of 5470 years is required.
This means 2 half-lives should have passed to remain a quarter of the sample.
<u>Step 2</u>: Calculate it's age
t/(t/1/2) = 2
⇒ with t = the age (or time) of the sample
⇒ with t(1/2) = the half-life time of the sample = 5470 years
⇒ with 2 = the number of halvf- lives passed
t/5470 = 2
t = 2*5470 = 10940 years
When there remains one-quarter of the sample, the age of the sample is 10940 years
Answer:
A.evidence to the existence of life
Explanation:
Answer:
[1] sulphur trioxide
Explanation:
Isoelectronic species have the same number of valence electrons.
Valence electrons in nitrate (NO₃⁻):
5e- (N) + (3 x 6e-)(3xO) + 1e- (charge) = 24e-
Valence electrons in sulphur trioxide (SO₃):
6e- (S) + (3 x 6e-)(3xO) = 24e-
Valence electrons in sulphite (SO₃²⁻):
6e- (S) + (3 x 6e-)(3xO) + 2e- (charge) = 26e-
Valence electrons in phosphine (PH₃):
5e- (P) + (3 x 1e-)(3xH) = 8e-
Valence electrons in water (H₂O):
6e- (O) + (2 x 1e-)(2xH) = 8e-
Valence electrons in chlorite (ClO₂⁻):
7e- (Cl⁻) + (2 x 6e-)(2xO) + 1e- (charge) = 20e-
The only species isoelectronic with nitrate is sulphur trioxide. Both have trigonal planar geoemetry.
Alpha particles are relatively heave and can be stopped by a sheet of paper.
Hydroxide ion is a strong and would react with H+ to form water
OH-+H+---->H2O
