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LiRa [457]
3 years ago
5

The first-order decay of radon has a half-life of 3.823 days. How many grams of radon remain after 7.22 days if the sample initi

ally weighs 250.0 grams?
Chemistry
1 answer:
Nesterboy [21]3 years ago
6 0

substitute: <span><span>t<span>1/2</span></span>=<span><span>ln(2)</span>k</span>→k=<span><span>ln(2)</span><span>t<span>1/2</span></span></span></span> Into the appropriate equation: <span>[A<span>]t</span>=[A<span>]0</span>∗<span>e<span>−kt</span></span></span> <span>[A<span>]t</span>=[A<span>]0</span>∗<span>e<span>−<span><span>ln(2)</span><span>t<span>1/2</span></span></span>t</span></span></span> <span>[A<span>]t</span>=(250.0 g)∗<span>e<span>−<span><span>ln(2)</span><span>3.823 days</span></span>(7.22 days)</span></span>=67.52 g</span>

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Katarina [22]

Answer:

8H2SO4 + 2KMnO4 + 5Na2O2 => 8H2O + 2MnSO4 + 5Na2SO4 + 5O2 + K2SO4

have:

Explanation:

6 0
3 years ago
Why is the base of an energy pyramid wider than the top
Zepler [3.9K]

It is due to a lack of providable energy to the next trophic level of the energy pyramid. Primary consumers only obtain around 10% of energy that producers have, and the energy depletes as you move further and further up the food chain, until you reach the tertiary consumers which have the least amount of energy at their disposal, meaning there are less of them than other organisms further down the energy pyramid.


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5 0
3 years ago
The reaction P4 +502P4010 + 712 kcal is
igor_vitrenko [27]

Answer:

The reaction is exothermic (option 4)

Explanation:

P4 + 5O2 → P4O10 + 712 kcal

In chemical reactions heat can be absorbed or released:

⇒in the first case, when heat is absorbed, this is called an endothermic reaction. The products have more energy than the reactants. The reaction requires or absorbs energy from it's surroundings.  That means  that in this reaction energy , in the form of heat, will be absorbed by the reactants.

⇒ when heat is released, this is called an exothermic reaction. The reactants have more energy than the products. The reaction gives or releases energy to it's surroundings.  That means  that in this reaction energy , in the form of heat, will be released by the reactants.

in the case of P4 + 5O2 → P4O10 + 712 kcal

We notice that on the right side, which is the product side, there is a positive amount of energy. This means that the energy is released by the the reactants, in this reaction. <u>The reaction is exothermic.</u>

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4 0
3 years ago
Read 2 more answers
Which has the higher percentage of aluminum, Al2O, or Al(NO3)3
Rzqust [24]

Al₂O  has a higher percentage of aluminium.

Explanation:

To solve this problem, we have to compare the molar mass of the aluminium in each compound to one another as percentage of the whole compound:

Molar mass of Al₂O = 2(27) + 16 = 70g/mol

Molar mass of Al(NO₃)₃ = 27 + 3[14 + 3(16)] = 213g/mol

Percentage by mass of Al in Al₂O = \frac{2x27}{70} x 100 = 77%

Percentage by mass of Al in  Al(NO₃)₃ = \frac{27}{213} x 100 = 12.7%

Al₂O  has a higher percentage of aluminium.

learn more:

Molar mass brainly.com/question/2861244

#learnwithBrainly

8 0
3 years ago
Describe how urine is removed from the blood and then eliminated from the body
Vlad [161]
Passes through the kidneys and the good stuff is kept, and the other stuff is passed through leading to the bladder.  The once the bladder is full enough to send the message to the brain, urine (waste) is eliminated from the body.
7 0
4 years ago
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