Question

Why is a homogeneous mixture not considered a pure substance? Question 6 options: A pure substance can be separated by physical means, while a mixture can be separated by chemical means. A pure substance can be separated by chemical means, while a mixture can be separated by physical means. Only heterogeneous mixtures are pure substances. A mixture contains one substance, while a pure substance contains more than one.What is true if mass is conserved in a reaction?
Question 7 options:

There are more atoms on the product side.


There are more atoms on the reaction side.


There are equal numbers of atoms on both sides.


The number of atoms on each side changes.

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Question 8 (1 point) Question 8 Unsaved
Methane reacts with oxygen to produce carbon dioxide and water. What are the products?



Question 8 options:

methane and water


methane and oxygen


oxygen and carbon dioxide


carbon dioxide and water

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Question 9 (1 point) Question 9 Unsaved
Which one of the following is not a homogeneous mixture?

Question 9 options:

vegetable soup


brewed tea


carbonated beverages


salt water solution

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Question 10 (1 point) Question 10 Unsaved
The following characteristics describe which of these terms? The substance is not uniform in appearance and each part of the mixture contains a combination of different ingredients in different ratios.

Question 10 options:

heterogeneous mixtures


homogeneous mixtures


pure substance


solution

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Question 11 (1 point) Question 11 Unsaved
If a solution is saturated, which of these is true?

Question 11 options:

More solute can be dissolved.


The solution has a low concentration of solute.


The concentration cannot be increased.


More solvent can be dissolved.

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Question 12 (1 point) Question 12 Unsaved
Which of these substances are molecules?

1. H2O

2. NaCl

3. N2

4. O2

Question 12 options:

None of them


3 and 4


1 and 2


All of them

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Question 13 (1 point) Question 13 Unsaved
What makes a solution a homogeneous mixture?

Question 13 options:

The mixture contains solids and liquids.


The mixture has multiple colors.


It is uniform in composition.


There is only one component.

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Question 14 (1 point) Question 14 Unsaved
Using the Law of Conservation of Matter, determine the number of grams of iron sulfide (FeS) that will be produced in this reaction.

112g Fe + 64g S → _____ g FeS

Question 14 options:

176 grams


64 grams


112 grams


48 grams

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Question 15 (1 point) Question 15 Unsaved
When a solute is added to a solution, why does it remain homogeneous?

Question 15 options:

The color concentrates at the bottom.


The solute dissolves.


It forms a compound.


It does not mix with water.

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Question 16 (1 point) Question 16 Unsaved
If Lavoisier heated 100 grams of powdered mercuric oxide to produce 93 grams of liquid mercury, how much oxygen would be released?

Question 16 options:

7 grams


16 grams


93 grams


32 grams

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Question 17 (1 point) Question 17 Unsaved
The chemical formula of glucose is C6H12O6, so it is classified as a(n)

Question 17 options:

mixture.


solution.


element.


pure substance.

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Question 18 (1 point) Question 18 Unsaved
How many chlorine (Cl) atoms would be in 4 molecules of salt (4 NaCl)?

Question 18 options:

4


2


3


1

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Question 19 (1 point) Question 19 Unsaved
In a solution of salt and water, which component is the solute?

Question 19 options:

beaker


water


oxygen


salt

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Question 20 (1 point) Question 20 Unsaved
These substances are all ____.

H2O2

Li

NaCl

O2

Question 20 options:

Pure Substances


Compounds


Elements


Molecules

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Question 21 (1 point) Question 21 Unsaved
If you have 5 grams of product after a chemical reaction, how many grams of reactants did you have at the start of the reaction?

Question 21 options:

3


4


2


5

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Question 22 (1 point) Question 22 Unsaved
What is the difference between a compound and a mixture?

Question 22 options:

You cannot separate mixtures, but you can separate compounds.


A compound is a pure substance, but a mixture is not.


Mixtures are chemically combined, but compounds are not.


A mixture is a pure substance, but a compound is not.

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Question 23 (1 point) Question 23 Unsaved
A firework exploding would be an example of a(n) ________.

Question 23 options:

Endothermic reaction


Formation of a precipitate


Physical change


Exothermic reaction

Answer 1

1. Why is a homogeneous mixture not considered a pure substance?

Answer:

• A pure substance can be separated by chemical means, while a mixture can be separated by physical means.

2. What is true if mass is conserved in a reaction?

Answer:

• There are equal numbers of atoms on both sides.

3. Methane reacts with oxygen then what are the products?

Answer:

• carbon dioxide and water

4. Which one of the following is not a homogeneous mixture?

Answer:

• vegetable soup

5. The substance is not uniform in appearance and each part of the mixture contains a combination of different ingredients in different ratios.

Answer:

• heterogeneous mixtures

6. If a solution is saturated, which of these is true?

Answer:

• More solvent can be dissolved

7. Which of these substances are molecules?

Answer:

• All compounds are molecules but not all molecules are compounds. Molecular oxygen (O2) and molecular nitrogen (N2) are not compounds because each is composed of a single element. So correct option is 3 and 4.

8. What makes a solution a homogeneous mixture?

Answer:

• It is uniform in composition.

9. When a solute is added to a solution, why does it remain homogeneous?

Answer:

• The solute dissolves.

10. The chemical formula of glucose is C6H12O6, so it is classified as a(n)

Answer:

• pure substance.

11. How many chlorine (Cl) atoms would be in 4 molecules of salt (4 NaCl)?

Answer:

• 4

12. In a solution of salt and water, which component is the solute?

Answer:

• Salt

13. These substances are all   H2O2,   Li , NaCl , O2

Answer:

• Pure Substances

14. If you have 5 grams of product after a chemical reaction, how many grams of reactants did you have at the start of the reaction?

Answer:

• 5

15. What is the difference between a compound and a mixture?

Answer:

• A compound is a pure substance, but a mixture is not.

16. A firework exploding would be an example of a(n) ________.

Answer:

• Exothermic reaction

17. If Lavoisier heated 100 grams of powdered mercuric oxide to produce 93 grams of liquid mercury, how much oxygen would be released?

Solution

                       2HgO ==> 2Hg + O2

Mass of HgO = 100 g

Molar mass of HgO = 216.59 g/mol

Moles = mass/molar mass = 0.46 moles

From balance chemcial equation

   HgO :  O2

      2  =    1

    0.46 = (1 × 0.46 ) ÷ 2 = 0.23 moles

mass of O2 = moles× molar mass = 0.23 × 32 = 7.36 g

18. Using the Law of Conservation of Matter, determine the number of grams of iron sulfide (FeS) that will be produced in this reaction.

Solution

                         12g Fe + 64g S → _____ g FeS

• According to Law of Conservation of Matter, The total mass of reactant is equal to total mass of  product , so the number of grams of iron sulfide (FeS) that will be produced in this reaction as follow.

                              12 + 64 = 76 g of FeS

Hope this Help.

 

Answer 2

23 would be

B) Endothermic reaction

because it is hotter than its surroundings