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givi [52]
3 years ago
11

The half-life is the amount of time it takes for one-half of an isotope sample to decay into a different element. The half-life

of 238U is 4.5 billion years. Other radioactive isotopes decay in a much shorter time. By comparison, the half-life of 14C (carbon 14) is approximately 5,700 years. Radiometric dating has calculated the age of the earth at approximately 4.6 billion years. Using a circle represent the amount of an isotope before decay has begun
Chemistry
1 answer:
katovenus [111]3 years ago
5 0

Answer:

idk but this is what i know only

Explanation:

he half-life is the amount of time it takes for one-half of an isotope sample to decay into a different element. The half-life of 238U is 4.5 billion years. Other radioactive isotopes decay in a much shorter time. By comparison, the half-life of 14C (carbon 14) is approximately 5,700 years. Radiometric dating has calculated the age of the earth at 215 approximately 4.6 billion years. 1. Which circle in Figure 13-2 represents the amount of the original isotope before decay began?A 2. Assume that Figure 13-2 represents the half-life of 238U. Color in the area of circles B, C, and D that represents the amount of 238U remaining in the rock layer as each half-life passes. 3. If Figure 13-2 represented the half-life of 238U, which circle that you colored would represent a rock layer with the greatest concentration of lead? _A__ 4. Which circle that you colored shows the amount of the original isotope remaining after two half-life periods have expired? 5. IT Figure 13-2 represented the half-life of 14C, how many years would have passea to reach letter D? years 70 um ens ghe ting Fie ni boe nibs D rlt to got no oA teB Lgoc velFIGURE 13-2. Half-Life of a Radioactive Isotope C teob

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18 An important environmental consideration is the appropriate disposal of cleaning solvents. An environmental waste treatment c
Katyanochek1 [597]

Answer:

a) Percentage by mass of carbon: 18.3%

   Percentage by mass of hydrogen: 0.77%

b)  Percentage by mass of chlorine: 80.37%

c) Molecular formula: C_{2} H Cl_{3}

Explanation:

Firstly, the mass of carbon must be determined by using a conversion factor:

0.872g CO _{2} *\frac{12g C}{44g CO_{2} } = 0.238g CO_{2}

The same process is used to calculate the amount of hydrogen:

0.089g H_{2}O*\frac{2g H}{18g H_{2}O }  = 0.010g H

The percentage by mass of carbon and hydrogen are calculated as follows:

%C\frac{0.238g}{1.3g} *100%= 18.3%

%H\frac{0.010g}{1.3g} *100%=0.77%

From the precipation data it is possible obtain the amount of chlorine present in the compound:

1.75 AgCl*\frac{35.45g Cl}{143.45g AgCl}= 0.43g AgCl

Let's calculate the percentage by mass of chlorine:

%Cl=\frac{0.43g}{0.535g} * 100%= 80.37%

Assuming that we have 100g of the compound, it is possible to determine the number of moles of each element in the compound:

18.3g C*\frac{1mol C}{12g C} = 1.52mol C

0.77g H*\frac{1mol H}{1g H} = 0.77mol H

80.37gCl*\frac{1molCl}{35.45g Cl} = 2.27mol Cl

Dividing each of the quantities above by the smallest (0.77mol), the  subscripts in a tentative formula would be

C=\frac{1.52}{0.77} = 1.97 ≈ 2

H = \frac{0.77}{0.77} = 1

Cl =\frac{2.27}{0.77}=2.94≈3

The empirical formula for the compound is:

C_{2} H Cl_{3}

The mass of this empirical formula is:

mass of C + mass of H + mass of Cl= 24g +1+ 106.35 =131.35g

This mass matches with the molar mass, which means that the supscript in the molecular formula are the same of the empirical one.

5 0
3 years ago
If three potatoes have a mass of 667 g, what will be the mass of 100 potatoes? A. 200 kg B. 22.2 kg C. 2223 g D. 20.0 kg
adell [148]

Answer: B- 22.2 kg

Explanation: If three potatoes have mass of 667 g that means that each potato weighs 667/3= 222.33 g (approx) so 100 potatoes must be 100*222.33= 22233 g which equals 22.2 kg because 1 g=1000 kg

8 0
3 years ago
How many moles are in a 111.5 gram sample of sodium chloride, NaCl?
Katarina [22]

Answer: 1.91 moles

Explanation:

First you want to find the molar mass of NaCL

Na = 22.99g  Cl = 35.45g

22.99g + 35.45g = 54.44g

Then divide 111.5g by 54.44g and this will give you moles.

5 0
2 years ago
How many moles of Na2Cr2O7 contain 14 moles of oxygen atoms?
sergiy2304 [10]
The number of moles of sodium dichromate from the number of moles of oxygen atoms can be determined through stoichiometry. Using the molecular formula of the compound, Na2Cr2O7, 1 mole of the compound contains 7 moles of oxygen. Hence, 14 moles O2*(1 mole Na2Cr2O7/ 7 mole O2) is equal to 2 moles <span>Na2Cr2O7.</span>
7 0
3 years ago
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Give the name of reaction in the<br> preparation of alkene from alcohol<br> compounds.
pickupchik [31]

Dehydration to alkenes!

3 0
3 years ago
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