Answer:
I’m pretty sure it’s Lions sleeping after a big meal
Explanation:
Physical changes occur when the properties of a substance are retained and/or the materials can be recovered after the change. Chemical changes involve the formation of a new substance. Formation of a gas, solid, light, or heat are possible evidence of chemical change.
Answer:
296.1 day.
Explanation:
- The decay of radioactive elements obeys first-order kinetics.
- For a first-order reaction: k = ln2/(t1/2) = 0.693/(t1/2).
Where, k is the rate constant of the reaction.
t1/2 is the half-life time of the reaction (t1/2 = 1620 years).
∴ k = ln2/(t1/2) = 0.693/(74.0 days) = 9.365 x 10⁻³ day⁻¹.
- For first-order reaction: <em>kt = lna/(a-x).</em>
where, k is the rate constant of the reaction (k = 9.365 x 10⁻³ day⁻¹).
t is the time of the reaction (t = ??? day).
a is the initial concentration of Ir-192 (a = 560.0 dpm).
(a-x) is the remaining concentration of Ir-192 (a -x = 35.0 dpm).
<em>∴ kt = lna/(a-x)</em>
(9.365 x 10⁻³ day⁻¹)(t) = ln(560.0 dpm)/(35.0 dpm).
(9.365 x 10⁻³ day⁻¹)(t) = 2.773.
<em>∴ t </em>= (2.773)/(9.365 x 10⁻³ day⁻¹) =<em> 296.1 day.</em>
The answer to this question is D! The ball and stick model! Hope this helps :)
Answer:
See explanation
Explanation:
% optical purity = specific rotation of mixture/specific rotation of pure enantiomer * 100/1
specific rotation of mixture = 23°
specific rotation of pure enantiomer = 61°
Hence;
% optical purity = 23/61 * 100 = 38 %
More abundant enantiomer = 100% - 38 % = 62%
Hence the pure (S) carvone is (-) 62° is the more abundant enantiomer.
Enantiomeric excess = 62 - 50/50 * 100 = 24%
Hence
(R) - carvone = 38 %
(S) - carvone = 62%