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2 years ago

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Calculate the density of a substance for which 4.78 x 106 L of the substance has a mass of 1.50 x 107 kg. Express your answer us

ing the correct number of significant figures, and do not enter your answer using scientific notation.

1 answer:

valentinak56 [21]2 years ago

4 0

7.89 is the correct answer I believe

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In the graph above for the dissociation of a strong acid, why do the bars for H3O+ and A- have the same height as the bar for HA

dimaraw [331]

Answer:

The concentration of HA is the same as concentration of H3O+ and A- produced.

Explanation:

The dissociation equation is given below:

HA(aq) + H2O (l) —> H3O+(aq) + A-(aq)

From the reaction above, we can see that the acid is monoprotic acid i.e it has only 1 ionisable hydrogen atom.

Now, from the balanced equation, we can see that the acid produced equal concentration of H3O+ and A-.

This account for the reason why the bars for H3O+ and A- have the same height as the bar for HA.

6 0

3 years ago

Determine whether or not the mixing of each of the two solutions indicated below will result in a buffer.

WARRIOR [948]

Part A

75.0 mL of 0.10 M HF; 55.0 mL of 0.15 M NaF

This combination will form a buffer.

Explanation

Here, weak acid HF and its conjugate base F- is available in the solution

Part B

150.0 mL of 0.10 M HF; 135.0 mL of 0.175 M HCl

This combination cannot form a buffer.

Explanation

Here, moles of HF = 0.15 x 0.1 = 0.015 moles

Moles of HCl = 0.135 x 0.175 = 0.023

Since HCl is a strong acid and the number of HCl is higher than HF. This prevents the dissociation of HF and the conjugate base F- will not be available in the solution

Part C

165.0 mL of 0.10 M HF; 135.0 mL of 0.050 M KOH

This combination will form a buffer.

Explanation

Moles of HF = 0.165 x 0.1 = 0.0165 moles

Moles of KOH = 0.135 x 0.05 = 0.00675 moles

Moles of KOH is not sufficient for the complete neutralization of HF. Thus weak acid HF and its conjugate base F- is available in the solution and form a buffer

Part D

125.0 mL of 0.15 M CH3NH2; 120.0 mL of 0.25 M CH3NH3Cl

This combination will form a buffer

Explanation

Here, weak acid CH3NH3+ and its conjugate base CH3NH2 is available in the solution and form a buffer

Part E

105.0 mL of 0.15 M CH3NH2; 95.0 mL of 0.10 M HCl

This combination will form a buffer

Explanation

Moles of CH3NH2 = 0.105 x 0.15 = 0.01575 moles

Moles of HCl = 0.095 x 0.1 = 0.0095 moles

Thus the HCl completely reacts with CH3NH2 and converts a part of the CH3NH2 to CH3NH3+. This results weak acid CH3NH3+ and its conjugate base CH3NH2 is in the solution and form a buffer

5 0

3 years ago

7.The equation below shows a process that occurs in all green plants.

pychu [463]

Answer:

Ⓓ The process follows the law of conservation of mass and energy is found in the product

Explanation:

This question depicts PHOTOSYNTHESIS, which is the process employed by green plants to manufacture their food in form of sugars (glucose). The general equation, which was given in the question is as follows:

6CO2 + 6H2O + energy → C6H12O6 + 6O2

This chemical reaction follows the LAW OF CONSERVATION OF MASS, which states that the amount of matter in reactant must equate that of the product. In this case, each element contains the same number of atoms in both reactant side and product side.

Also, energy is contained in the product but stored in the chemical bonds of the glucose molecule formed.

6 0

3 years ago

Potassium superoxide, KO2, reacts with carbon dioxide to form potassium carbonate and oxygen: This reaction makes potassium supe

kramer

Answer:

There will be produced 0.8448 grams O2

Explanation:

<u>Step 1:</u> Data given

Mass of KO2 = 2.50 grams

Mass of CO2 = 4.50 grams

Molar mass KO2 = 71.1 g/mol

Molar mass of CO2 = 44.01 g/mol

Molar mass of O2 = 32 g/mol

<u>Step 2:</u> The balanced equation

4 KO2(s) + 2 CO2(g) → 2 K2CO3(s) + 3 O2(g)

<u>Step 3</u>: Calculate moles KO2

Moles KO2 = mass KO2 / Molar mass KO2

Moles KO2 = 2.50 grams / 71.1 g/mol

Moles KO2 = 0.0352 moles

<u>Step 4:</u> Calculate moles of CO2:

Moles CO2 = mass CO2 / Molar mass CO2

Moles CO2 = 4.50 grams / 44.01 g/mol

Moles CO2 = 0.102 moles

<u>Step 5:</u> calculate limiting reactant

For 4 moles of KO2 consumed, we need 2 moles of CO2 to produce 2 moles of K2CO3 and 3 moles of O2

KO2 is the limiting reactant. It will completely be consumed. (0.0352 moles).

CO2 is in excess. There will react 0.0352/2 = 0.0176 moles of CO2

There will remain 0.102 - 0.0176 = 0.0844 moles CO2

<u>Step 6</u>: Calculate moles O2 produced

For 4 moles of KO2 consumed, we need 2 moles of CO2 to produce 2 moles of K2CO3 and 3 moles of O2

For 0.0352 moles KO2 consumed, we have 3/4 * 0.0352 = 0.0264 moles of O2 produced

<u>Step 7</u>: Calculate mass of 02 produced

Mass O2 produced = Moles O2 * Molar mass 02

Mass O2 produced = 0.0264 moles * 32 g/mol

Mass O2 produced = 0.8448 grams O2

There will be produced 0.8448 grams O2

5 0

2 years ago

Which answer shows an example of transmutation? salt and water mixing to make salt water wood burning to make smoke and ash lead

rjkz [21]

Answer is: <span>lead changing to gold.
</span>Transmutation is the conversion of an atom of one element to an atom of another through nuclear reactions. N<span>umber of protons or neutrons in the nucleus is changed. </span>Particle accelerators and nuclear reactors used for creating elements.

8 0

3 years ago

Read 2 more answers