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Aneli [31]
3 years ago
11

9. How long will it take 120 grams of Strontium-90 to decay to 7.5 grams?with steps pls​

Chemistry
1 answer:
ryzh [129]3 years ago
5 0

Answer:

116 years

Explanation:

To solve this, we will use the half life equation;

A(t) = A_o(½)^(t/t_½)

Where;

A(t) is the amount of strontium left after t years;

A_o is the initial quantity of strontium that will undergo decay;

t_½ is the half-life of strontium

t is the time it will take to decay

We are given;

A(t) = 7.5 g

A_o = 120 g

From online values, half life of strontium-90 is 29 years. Thus, t_½ = 29

Thus;

7.5 = 120 × ½^(t/29)

Divide both sides by 120 to get;

7.5/120 = ½^(t/29)

0.0625 = ½^(t/29)

In 0.0625 = (t/29) In ½

-2.772589 = (t/29) × (-0.693147)

(t/29) = -2.772589/(-0.693147)

t/29 = 4

t = 29 × 4

t = 116 years

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when obtaining energy, why mushrooms are more like elephants eating and not like dandelions absorbing sunlight.
Julli [10]

Answer:

Because they lack chlorophyll (a green pigment in plants that helps them trap sunlight, used to manufacture their food through photosynthesis)

Explanation:

Mushrooms are heterotrophs. They are not plants or autotrophs. Mushrooms, just like every living thing that exists need energy in order to live. Only plants, or autotrophs, can directly use energy from the sun (the ultimate energy) to make food. Those organisms that cannot harness the sun's energy are known as heterotrophs. Mushrooms are fungi (belong to kingdom Fungi) and are heterotrophs because they decompose and consume nutrients from the soil. They are not green so they cannot photosynthesis due to lack of chlorophyll.

6 0
3 years ago
A gas under a pressure of 74 mmHg and at a temperature of 75°C occupies a 500.0-L container. How many moles of gas are in the co
Leona [35]

Answer : The number of moles of gas present in container are 1.697 mole.

Explanation :

Using ideal gas equation,

PV=nRT

where,

P = pressure of gas = 74 mmHg = 0.097 atm

conversion used : (1 atm = 760 mmHg)

V = volume of gas = 500.0 L

T = temperature of gas = 75^oC=75+273=348K

n = number of moles of gas = ?

R = gas constant = 0.0821 L.atm/mole.K

Now put all the given values in the ideal gas equation, we get the number of moles of gas in the container.

(0.097atm)\times (500.0L)=n\times (0.0821L.atm/mole.K)\times (348K)

n=1.697mole

Therefore, the number of moles of gas present in container are 1.697 mole.

4 0
3 years ago
Why are metals malleable?
Tema [17]

Answer:

b is the anwer

Explanation:

the option is the explanation

4 0
3 years ago
How can professionals increase their levels of stress as a result of personal work habits?
zmey [24]

Answer:

A

Explanation:

Developing work ethics won't lower your stress although it may make your conscience a little happier. Not B

Not C. Procrastinating just makes things harder. The mountain of things to do is not diminishing at all and your stress knows it.

Not D. Although D is the second best answer, setting goals is not really an action. It is a plan for how to work. But it is not work. Still having a goal is useful.

The answer is A. Just keep hitting what you have to do at a steady pace.

8 0
3 years ago
Ammonia is produced industrially via this exothermic reaction.
Cloud [144]

Answer:

high pressure of 200-300 atm.

low temp. of between 400-500 degrees celsius:this is for continuous development of ammonia since it decomposes at high temp fathermore the reaction is exothermic

a catalyst to speed up the rate of reaction:i guess it is finely divided iron impregnated in aluminium oxide

platinum can be used as a catalyst but it is easily poisoned

hope it helps

Explanation:

6 0
3 years ago
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