Answer:
3.91 minutes
Explanation:
Given that:
Biacetyl breakdown with a half life of 9.0 min after undergoing first-order reaction;
As we known that the half-life for first order is:
where;
k = constant
The formula can be re-written as:
Let the initial amount of butter flavor in the food be 
= 100%
Also, the amount of butter flavor retained at 200°C 
= 74%
The rate constant
To determine how long can the food be heated at this temperature and retain 74% of its buttery flavor; we use the formula:
Substituting our values; we have:
t = 3.91 minutes
∵ The time needed for the food to be heated at this temperature and retain 74% of its buttery flavor is 3.91 minutes
Answer: A. The compound CuCl is 500 times less soluble in sea water than it is in pure water.
pure water.
Explanation:
Any change in the equilibrium is studied on the basis of Le-Chatelier's principle.
This principle states that if there is any change in a equilibrium reaction, the equilibrium will shift in a direction so as to minimize the effect.
Thus when a common ion is introduced to an equilibrium reaction, the equilibrium will shift in a direction where the concentration of common ion is decreasing.
When common ion such as 
from NaCl in sea water is introduced to an equilibrium reaction, the equilibrium will shift in a direction where the concentration of common ion is decreasing i.e. in the left side and thus solubility of CuCl further decreases.
A decomposition reaction.
ΔH=MCΔT
ΔH=100 x 4.2 x 4
ΔH=1680
ΔH per mole = ΔH ÷ moles
ΔH per mole = 1680 ÷ 0.02
<span>ΔH per mole= 84000Jmol
</span>84000 ÷ 1000 = 84KJmol
its exothermic as heat is given out into the solution
The sun doesn't heat the air much directly because the radiation is all visible light, which isn't easily absorbed by gases in the atmosphere. So I would disagree
