Answer:
star
Explanation:
stars are composed of 92.1 percent hydrogen and 7.8 percent helium.
Well theres 5 so times 2 equals 10
The molecular mass of Carvone is calculated as;
= 12 (C)₁₀ + 1.008 (H)₁₄ + 16 (O)
= 120 + 14.112 + 16
= 150.112
%age of Carbon;
= (120 ÷ 150.112) × 100
= 79.94 %
%age of Hydrogen;
= (14.112 ÷ 150.112) × 100
= 9.40 %
%age of Oxygen;
= (16 ÷ 150.112) × 100
= 10.65 %
Answer:
1.146 x 10⁴ year.
Explanation:
- The decay of carbon-14 is a first order reaction.
- The rate constant of the reaction (k) in a first order reaction = ln (2)/half-life = 0.693/(5730 year) = 1.21 x 10⁻⁴ year⁻¹.
- The integration law of a first order reaction is:
<em>kt = ln [A₀]/[A]</em>
<em></em>
k is the rate constant = 1.21 x 10⁻⁴ year⁻¹.
t is the time = ??? years.
[A₀] is the initial percentage of carbon-14 = 100.0 %.
[A] is the remaining percentage of carbon-14 = 1/4[A₀] = 25.0 %.
∵ kt = ln [Ao]/[A]
∴ (1.21 x 10⁻⁴ year⁻¹)(t) = ln (100.0%)/[25.0 %]
(1.21 x 10⁻⁴ year⁻¹)(t) = 1.386.
∴ <em>t </em>= 1.386/
(1.21 x 10⁻⁴ year⁻¹) = <em>1.146 x 10⁴ year.</em>
