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Nimfa-mama [501]
3 years ago
13

Three radioisotopes are being discussed in a chemistry class. Technetium-99m has a half-life of 6 hours. Rubidium-87 has a half-

life of 50 billion years. Which describes who would most likely use each isotope?
Chemistry
2 answers:
8_murik_8 [283]3 years ago
5 0
A likely application of a radioactive isotope with a short half-life such as Technetium-99 will be as a medical tracer. It will likely be used by a doctor to check the movement of substances within a person's body.

A radioactive isotope with such a long half-life like Rubidium-87 is likely used in the determination of the age of fossils and artifacts found by archaeologists.<span />
adelina 88 [10]3 years ago
3 0

The answer is B. "A doctor would use technetium-99m because a short half-life indicates a quick measurement, and a geologist would use rubidium-87 because a longer half-life means that there is a longer time to measure old rock" on edg

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What is the ionic charge for C, Si, Ge, Sn and Pb?
Alecsey [184]
An atom of carbon has 4 electrons in its outermost shell, which means that 
<span>its ionic charge is 4+ or 4-
</span>Si is in same group as carbon so its also 4+ or 4-
Germanium is 4+.
Sn is also 2+ or 4+
Pb is usually +2


6 0
2 years ago
Gaseous methane reacts with gaseous oxygen gas to produce gaseous carbon dioxide and gaseous water. If 2.59 g of water is produc
max2010maxim [7]

<u>Answer:</u> The percent yield of the water is 31.98 %

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}     .....(1)

  • <u>For methane:</u>

Given mass of methane = 6.58 g

Molar mass of methane = 16 g/mol

Putting values in equation 1, we get:

\text{Moles of methane}=\frac{6.58g}{16g/mol}=0.411mol

  • <u>For oxygen gas:</u>

Given mass of oxygen gas = 14.4 g

Molar mass of oxygen gas = 32 g/mol

Putting values in equation 1, we get:

\text{Moles of oxygen gas}=\frac{14.4g}{32g/mol}=0.45mol

The chemical equation for the combustion of methane is:

CH_4+2O_2\rightarrow CO_2+2H_2O

By Stoichiometry of the reaction:

2 moles of oxygen gas reacts with 1 mole of methane

So, 0.45 moles of oxygen gas will react with = \frac{1}{2}\times 0.45=0.225mol of methane

As, given amount of methane is more than the required amount. So, it is considered as an excess reagent.

Thus, oxygen gas is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction

2 moles of oxygen gas produces 2 moles of water

So, 0.45 moles of oxygen gas will produce = \frac{2}{2}\times 0.45=0.45 moles of water

  • Now, calculating the mass of water from equation 1, we get:

Molar mass of water = 18 g/mol

Moles of water = 0.45 moles

Putting values in equation 1, we get:

0.45mol=\frac{\text{Mass of water}}{18g/mol}\\\\\text{Mass of water}=(0.45mol\times 18g/mol)=8.1g

  • To calculate the percentage yield of water, we use the equation:

\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100

Experimental yield of water = 2.59 g

Theoretical yield of water = 8.1 g

Putting values in above equation, we get:

\%\text{ yield of water}=\frac{2.59g}{8.1g}\times 100\\\\\% \text{yield of water}=31.98\%

Hence, the percent yield of the water is 31.98 %

4 0
3 years ago
How many moles of nacl are required to make 250 ml of a 3.00 m solution?
choli [55]
The molarity is calculated using the following rule:
molarity = number of moles of solvent / volume of solution (in liters)

We have the volume of solution = 250 ml = 0.25 liters and the molarity = 3 m

Substituting in the equation, we get:
3 = number of moles / 0.25
number of moles = 3 x 0.25 = 0.75 moles
4 0
3 years ago
Which prefix indicates a molecule with 2 carbon atoms?
aleksandrvk [35]
The answer is A. Eth-
7 0
2 years ago
What are all four Quantum numbers of 11th electron of magnesium​
ruslelena [56]

Answer:n=0

l=0

ml=0

ms = =1/2 or +1/2

Explanation:

3 0
3 years ago
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