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3 years ago

32. A sample of potassium is composed of 23% K-39, 48% K-40 and the remainder K-41. Calculate the average mass

Chemistry

1 answer:

mario62 [17]3 years ago

7 0

Answer:

40.06 amu.

Explanation:

From the question given above, the following data were obtained:

Isotope A (K-39)

Mass of A = 39 amu

Abundance of A = 23%

Isotope B (K-40)

Mass of B = 40 amu

Abundance of B = 48%

Isotope C (K-41)

Mass of C = 41 amu

Abundance of C = 100 – (23 + 48)

Abundance of C = 100 – 71

Abundance of C = 29%

Average mass =?

Average mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100]

= [(39 × 23)/100] + [(40 × 48)/100] + [(41 × 29)/100]

= 8.97 + 19.2 + 11.89

= 40.06 amu

Thus, the average mass of potassium is 40.06 amu

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inn [45]

<span>7.2 g of water.

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3 years ago

Calcium carbonate decomposes when heated to solid calcium oxide and carbon dioxide gas. The balanced equation is: CaCO3(s) → CaO

wlad13 [49]

Answer:

The mass of CaCO3 reacted is 5.00 grams

Explanation:

Step 1 :Data given

Before the reaction, the container, including the CaCO3, had a mass of 24.20 g

After the reaction the container with product had a mass of only 22.00 g because the CO2 gas produced did not remain in the container.

Molar mass of CO2 = 44.01 g/mol

Molar mass CaCO3 = 100.09 g/mol

Step 2: The balanced equation

CaCO3 → CaO + CO2

Step 3: Calculate mass of CO2

Mass of CO2 = 24.20 grams - 22.00 grams

Mass of CO2 = 2.20 grams

Step 4: Calculate moles CO2

Moles CO2 = mass CO2 / molar mass CO2

Moles CO2 = 2.20 grams / 44.01 g/mol

Moles CO2 = 0.0500 moles

Step 5: Calculate moles CaCO3

For 1 mol CaCO3 we'll have 1 mol CaO and 1 mol CO2

For 0.0500 moles CO2 we need 0.0500 moles CaCO3

Step 6: Calculate mass CaCO3

Mass CaCO3 = moles CaCO3 * molar mass CaCO3

Mass CaCO3 = 0.0500 moles * 100.09 g/mol

Mass CaCO3 = 5.00 grams

The mass of CaCO3 reacted is 5.00 grams

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3 years ago

Whats the name of CaS?

sergejj [24]

Answer

Chemical formula or Chemical Abstracts Service

Explanation:

A CAS (Chemical Abstracts Service) Registry Number is a unique identifier that tells you, for example, that acetone and dimethyl ketone are actually the same substance.

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3 years ago

Read 2 more answers

A researcher accidentally spilled some sand into his beaker containing crystalline compound X. Knowing what he did about melting

skad [1K]

Answer:

See explanation

Explanation:

If we look at the structure of X, we will discover that X is an organic compound. The compound will certainly have a much lower melting point than sand.

This is because, sand is composed of high melting point inorganic materials.

Hence, even though the researcher accidentally spilled some sand into the the beaker containing the crystalline substance X, he does not need to be perturbed since the melting point of X is much lower than that of sand

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3 years ago

(a) a 0.2 m potassium hydroxide solution is titrated with a 0.1 m nitric acid solution. (i) balanced equation: (ii)what would be

Stells [14]

$\text{KOH} (aq) + \text{HNO}_3 (aq) \to \text{KNO}_3 (aq) + \text{H}_2\text{O} (l)$

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The question states that the solution is "titrated with a ... nitric acid solution" indicating that $\text{HNO}_3$ is added to the initially-basic solution. PH value of the solution would keep decreasing as the volume of the acid added increases. The final solution would be acidic as it contains not only water and $\text{KNO}_3 (aq)$ , but some $\text{HNO}_3$ as well. Bromothymol blue would therefore demonstrates a yellow color, the color it present in an acidic solution, at the end of the titration.

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