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3 years ago

Please answer!

1 answer:

5 0

1.) A compound is a substance that originates from two or more separate elements. It shares some similarities with a mixture.

2.) A compound has quite different properties from which it was formed. It also cannot be separated easily. Compounds are formed by chemical reactions.

3.) A pure substance has a constant composition and has consistent properties. It can be a compound or an element, but its composition is constant.

Hope this helps. :)

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Why is a homogeneous mixture not considered a pure substance? Question 6 options: A pure substance can be separated by physical

krok68 [10]

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:

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:

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.

3 0

3 years ago

Read 2 more answers

What do you think is meant by the statement "the digestive system is very different

Kryger [21]

It could possibly refer to “the small intestines absorb most of the nutrients in food, and your circulatory system passes them on to other parts of your body to store or use. Special cells help absorbed nutrients cross intestinal lining into your bloodstream” hope this helps Good luck

7 0

3 years ago

Are scientific theories all proven facts?

SSSSS [86.1K]

No! That’s why they’re called theories. Most of them have a lot of facts to back it up however the theories themselves are either proven or just hypothetical.

8 0

3 years ago

Read 2 more answers

What is a form of potential energy that is due to relative positions of the particles within a materials.

Salsk061 [2.6K]

I think is D I hope it helped :)

4 0

3 years ago

what mass of sodium fluoride (FW=42.0 g/mol) must be added to 3.50 x 10^2 mL of water to give a solution with pH = 8.40?

MaRussiya [10]

Answer:

Explanation:

Sodium fluoride, being a salt, dissolves in water completely producing F ⁻ ions. Now F⁻ is the conjugate base of the weak acid HF, so in water we will have the following equilibrium:

F⁻ + H₂O ⇆ HF + OH⁻

Given this equilibrium, we need to calculate Kb from the Ka for HF, the [ OH ⁻] from the given pH, and finally the mass needed to produce that OH⁻ concentration.

The equilibrium constant, Kb , can be calculated from Kw = Ka x Kb, where Kw = 10⁻¹⁴ and Ka for HF is 6.6 x 10⁻⁴ from reference tables.

Kb = 10⁻¹⁴ / 6.6 x 10⁻⁴ = 1.5 x 10⁻¹¹

pH + pOH = 14 ⇒ pOH = 14 - 8.40 = 5.60

[ OH⁻ ] = 10^-5.60 = 2.51 x 10⁻⁶

Now we have all the information :

F⁻ HF OH⁻

Equilibrium X 2.51 x 10⁻⁶ 2.51 x 10⁻⁶

(2.51 x 10⁻⁶)² / X = 1.5 x 10⁻¹¹ ⇒ X = (2.51 x 10⁻⁶)² / 1.5 x 10⁻¹¹

X = [ F⁻ ] = 0.41 M

For 350 mL ( 0.35 L ) we need to add:

0.41 mol HF/ 1 L * 0.35 L = 0.144 mol

and finally the mass will be:

0.144 mol NaF * 42.0 g/mol NaF = 6.03 g NaF

7 0

3 years ago