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elena-14-01-66 [18.8K]
2 years ago
14

The half-life of 131I is 80 days. How much of a 500.0 mg sample remains after 3 half lives?

Chemistry
1 answer:
I am Lyosha [343]2 years ago
6 0

Answer:

62.5 mg

Explanation:

Just multiply the original amount by  1/2   three times:

500 mg  x  1/2  x  1/2  x  1/2 = 62.5 mg

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sdas [7]
Fats , oils , waxes and sterols are collectively known as lipidsand the true fats contain only carbon , hydrogen and oxygen 

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3 years ago
a solution is prepared by dissolving 55g of CaCl2 into 300g of water. if the Kf of water is -1.86 c/m, shat is the freezing poin
Zepler [3.9K]

Answer:

Relation between , molality and temperature is as follows.

                T =

It is also known as depression between freezing point where, i is the Van't Hoff factor.

Let us assume that there is 100% dissociation. Hence, the value of i for these given species will be as follows.

         i for  = 3

          i for glucose = 1

          i for NaCl = 2

Depression in freezing point will have a negative sign. Therefore, d

depression in freezing point for the given species is as follows.

       

                 =

       

                  =

     

                   =

Therefore, we can conclude that given species are arranged according to their freezing point depression with the least depression first as follows.

                    Glucose < NaCl <

Explanation:

3 0
3 years ago
Which term describes atoms with<br> unpaired dots in their electron dot<br> diagrams?
IRISSAK [1]

Answer:

Radicals

Explanation:

A radical refers to a chemical specie that contains unpaired electrons in their dot electron diagrams.

Radicals contain an odd number of electrons. They are commonly called odd electron species.

Radicals participate in a number of important reactions. A typical example is the halogenation of alkanes in the presence of light.

Examples of radicals include; Br. , Cl. , F. etc

8 0
3 years ago
How much energy must a 10 gram block of ice gain in order to melt ?
Minchanka [31]

Answer:

the answer is 10 times

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8 0
2 years ago
The atomic mass of magnesium is the weighted average of the atomic masses of
Debora [2.8K]

Answer:

2. All the naturally occurring isotopes of Mg.

Explanation:

You want to know the atomic mass of the magnesium you use in the lab. That’s “natural” magnesium. So, you must use the weighted average of all the naturally occurring isotopes in natural Mg.

1. and 3. are <em>wrong</em>. You won’t get the correct mass for natural Mg if you use only the artificial isotopes for your calculation.

4. is <em>wrong</em>. You must use all the naturally occurring isotopes. The two most abundant isotopes of Mg account for only 90 % of the atoms. If you ignore the other 10 %, your calculation will be wrong.

6 0
3 years ago
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