Answer : The time required for decay is, 84 days.
Explanation :
Half-life of chromium-51 = 28 days
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the time required for decay.
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = time taken by sample = ?
a = let initial activity of the sample = 100
a - x = amount left after decay process = 12.5
Now put all the given values in above equation, we get
Therefore, the time required for decay is, 84 days.
Answer:
The answer is 1.15m.
Since molality is defined as moles of solute divided by kg of solvent, we need to calculated the moles of H2SO4 and the mass of the solvent, which I presume is water.
We can find the number of H2SO4 moles by using its molarity
C=nV→nH2SO4=C⋅VH2SO4=6.00molesL⋅48.0⋅10−3L=0.288
Since water has a density of 1.00kgL, the mass of solvent is
m=ρ⋅Vwater=1.00kgL⋅0.250L=0.250 kg
Therefore, molality is
m=nmass.solvent=0.288moles0.250kg=1.15m
Answer:
Your answers are solids, liquids, and gases.
Explanation:
These are the three states of matter.
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Answer:
Unevenly
Explanation:
Fresh water is distributed unevenly in both time and space.
Answer: Positive effects: mass production of fertilizers, alkaline cleansers, refrigerant gas, dyes, explosives
Negative effects: heath problems, negative effects on soil organisms and soil organic matter, imbalances to the nitrogen cycle, high fossil fuel energy inputs, production of deadly weapons
Explanation:
The Haber process (also called Haber Bosch process) is used to produce ammonia from nitrogen and hydrogen under the high pressure. Basically, it's an artificial nitrogen fixation process. This method has both positive and negative effects on modern society.
Positive sides: ammonia is mainly used for mass production of fertilizer, which allows more food for everyone. It can be used for production of alkaline cleansers, refrigerant gas, dyes and explosives. Ammonia is also used in production of synthetic polymers, due to its role in the manufacturing of cyanide.
Negative sides: ammonia is a toxic gas, it can irritate eyes and lungs. Because of that, the excess nitrogen in soil and water coming from synthetic fertilizers can cause health problems. It is harmful for humans and animals, but it can also be harmful for plants. Environmental factors are also important. Because of the mass fixation, there is imbalance in the earth’s nitrogen cycle. Also, fossil fuels are used as a source of power for machinery in Haber's process, which increases emissions into the atmosphere. And, at least ammonia is a major component of weapons including great number of bombs.
