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ira [324]
3 years ago
7

43. We have a radioactive isotope called RI which has a half-life of 12 million years. A geologist

Chemistry
1 answer:
ioda3 years ago
8 0

Answer: Thus 3 half lives have taken place.

Explanation:

Expression for rate law for first order kinetics is given by:

t=\frac{2.303}{k}\log\frac{a}{a-x}

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process  

a) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

t_{\frac{1}{2}}=\frac{2.303}{k}\log\frac{100}{50}

t_{\frac{1}{2}}=\frac{0.693}{k}

Number of half lives =\frac{\text {total time}}{\text {half life}}=\frac{36million}{12million}=3

Thus 3 half lives have taken place.

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Answer:

Explanation:

You have an acid that is acidic or a base that is basic. When you mix the two, they form water (assuming those are bronsted-lowry acids and bases) which is neutral.

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3 years ago
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State the Periodic Law. Why is it so important in the study of chemistry?
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8 0
3 years ago
As you move upward, from level, in an energy pyramid, available energy ____.
svetlana [45]

The available energy decreases as one moves upward in an energy pyramid.

<h3>Energy pyramid</h3>

The energy pyramid represents a model of how energy is transferred from one trophic level to another in ecosystems.

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More on energy pyramid can be found here: brainly.com/question/2515928

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8 0
2 years ago
Explain how a plant is adapted for photosynthesis
snow_lady [41]

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4 0
2 years ago
What volume of 1.00 m hcl in liters is needed to react completely (with nothing left over) with 0.750 l of 0.100 m na2co3?
kotykmax [81]
The balanced equation for the reaction is as follows
Na₂CO₃ + 2HCl --> 2NaCl + CO₂ + H₂O
stoichiometry of Na₂CO₃ to HCl is 1:2
number of Na₂CO₃ moles reacted = molarity x volume
number of Na₂CO₃ moles = 0.100 mol/L x 0.750 L = 0.0750 mol 
according to molar ratio of 1:2
1 mol of Na₂CO₃ reacts with 2 mol of HCl
then 0.0750 mol of Na₂CO₃ mol reacts with - 2 x 0.0750 = 0.150 mol 
molarity of given HCl solution is 1.00 mol/L
molarity is defined as the number of moles of solute in 1 L of solution 
there are 1.00 mol in 1 L of solution 
therefore there are 0.150 mol in - 0.150 mol / 1.00 mol/L = 0.150 L 
volume of HCl required is 0.150 L 
3 0
3 years ago
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