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iren2701 [21]
3 years ago
7

Uranium-234 decays to lead-214 through a series of alpha decays. Which of the following is the total number of alpha particles e

mitted in this decay series?
A. 1
B. 2
C. 5
D. 10
Chemistry
1 answer:
wariber [46]3 years ago
4 0
An alpha particle has a mass number of 4.
The mass number in the decay of uranium-234 to lead-214 decreases from 234 to 214, so by 20.
20 ÷ 4 = 5
5 alpha particles were emitted in this decay series. The answer is C.
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Enter your answer in the provided box. A person's blood alcohol (C2H5OH) level can be determined by titrating a sample of blood
Annette [7]

<u>Answer:</u> The mass percent of alcohol in blood is 0.183 %

<u>Explanation:</u>

To calculate the moles for given molarity, we use the equation:

\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}

Molarity of Cr_2O_7^{2-} solution = 0.05961 M

Volume of solution = 35.46 mL = 0.03546 L   (Conversion factor:  1 L = 1000 mL)

Putting values in above equation, we get:

0.05961M=\frac{\text{Moles of }Cr_2O_7^{2-}}{0.03546L}\\\\\text{Moles of }Cr_2O_7^{2-}=(0.05961mol/L\times 0.03546L)=2.11\times 10^{-3}mol

The given chemical reaction follows:

16H^+(aq.)+2Cr_2O_7^{2-}(aq.)+C_2H_5OH(aq.)\rightarrow 4Cr^{3+}(aq.)+2CO_2(g)+11H_2O(l)

By Stoichiometry of the reaction:

2 moles of dichromate ions react with 1 mole of ethanol.

So, 2.11\times 10^{-3}mol of dichromate ions will react with = \frac{1}{2}\times 2.11\times 10^{-3}=1.06\times 10^{-3}mol

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

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}

Moles of ethanol = 1.06\times 10^{-3}mol

Molar mass of ethanol = 46.07 g/mol

Putting values in above equation, we get:

1.06\times 10^{-3}mol=\frac{\text{Mass of ethanol}}{46.07g/mol}\\\\\text{Mass of ethanol}=(1.06\times 10^{-3}mol\times 46.07g/mol)=0.0488g

  • To calculate the mass percent of ethanol in blood, we use the equation:

\text{Mass percent of ethanol}=\frac{\text{Mass of ethanol}}{\text{Mass of blood plasma}}\times 100

Mass of blood plasma = 26.60 g

Mass of ethanol = 0.0488 g

Putting values in above equation, we get:

\text{Mass percent of ethanol}=\frac{0.0488g}{26.60g}\times 100=0.183\%

Hence, the mass percent of alcohol in blood is 0.183 %

5 0
3 years ago
Below are shown, for five metals, reduction reactions and standard electrode potential values. which of these metals is the leas
just olya [345]
Above question is incomplete. Complete question is attached below
........................................................................................................................
Solution:
Reduction potential of metal ions are provided below. Higher the value to reduction potential, greater is the tendency of metal to remain in reduced state.

In present case, reduction potential of Au is maximum, hence it is least prone to undergo oxidation. Hence, it is least reactive.

On other hand, reduction potential of Na is minimum, hence it is most prone to undergo oxidation. Hence, it is most reactive. 


7 0
4 years ago
Which one of the following Acids is most likely to hurt you? Acid A: 1.0 M; Acid B: 0.0001M
vaieri [72.5K]
Acid A, assuming the two acids have the same pH. The M stands for molarity which is how concentrated a substance is (basically the higher the molarity the more concentrated the acid is). However, pH refers to how acidic a substance is. If the two acids have different levels of acidity, the answer may be different.
7 0
3 years ago
What is the relationship between molar mass in grams per mole (g/mol) and average atomic mass in amu of each element?
navik [9.2K]

Answer:

The molar mass and atomic mass are essentially the same for an element

Explanation:

The molar mass of a substance can be obtained by dividing the mass of the substance by the no of moles of the substance present.

The atomic mass of an element is the number of protons and neutrons present in the substance.

These two measurements usually give the same values because they both make reference to the 1/12th the mass of carbon-12  for their measurement.

Because they both have the same reference point, though they have different calculating procedures, the results obtained will be similar.

8 0
3 years ago
What is the molarity of a solution that has 23.0 g of NaOH dissolved in 0.500 L of solution?
madreJ [45]

Answer: 1.15M

Explanation:

Given that,

Amount of moles of NaOH (n) = ?

Mass of NaOH in grams = 23.0g

For molar mass of NaOH, use the atomic masses: Na = 23g; O = 16g; H = 1g

NaOH = (23g + 16g + 1g)

= 40g/mol

Since, n = mass in grams / molar mass

n = 23.0g / 40.0g/mol

n = 0.575 mole

Volume of NaOH solution (v) = 0.5 L

Concentration of NaOH solution (c) = ?

Since concentration (c) is obtained by dividing the amount of solute dissolved by the volume of solvent, hence

c = n / v

c = 0.575 mole / 0.5L

c = 1.15 M (M stands for molarity and gives the concentration in moles per litres)

Thus, the molarity of the solution is 1.15M

5 0
3 years ago
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