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Artyom0805 [142]
3 years ago
13

I'm not really sure on how to test if it is a chemical or physical change....

Chemistry
1 answer:
kolezko [41]3 years ago
4 0
Chemical change because it cannot be reversed
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Nothing at all happens because pure water cannot conduct electricity
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What is the name of the aluminum ion? Al–1 Al+2 Al–3 Al+3
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Most transition metal form more than one cation but aluminum forms the Al3+ cation only.

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Which word is the longest word in chemistry?​
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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?

<u><em>Answer:</em></u>

  • 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?

<em><u>Answer:</u></em>

  • There are equal numbers of atoms on both sides.

3. <em>Methane reacts with oxygen then what are the products?</em>

<u><em>Answer:</em></u>

  • carbon dioxide and water

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

<u><em>Answer:</em></u>

  • 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.

<u><em>Answer:</em></u>

  • heterogeneous mixtures

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

<u><em>Answer:</em></u>

  • More solvent can be dissolved

7. Which of these substances are molecules?

<u><em>Answer:</em></u>

  • 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?

<u><em>Answer:</em></u>

  • It is uniform in composition.

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

<em>Answer:</em>

  • The solute dissolves.

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

<u><em>Answer:</em></u>

  • pure substance.

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

<u><em>Answer:</em></u>

  • 4

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

<u><em>Answer:</em></u>

  • Salt

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

<u><em>Answer:</em></u>

  • 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?

<em>Answer:</em>

  • 5

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

<u><em>Answer:</em></u>

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

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

<u><em>Answer:</em></u>

  • 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.

<em><u>Solution</u></em>

                         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
You have a 28.2-g sample of a metal heated to 95.2°c. you drop it in a calorimeter with 100. g of water at 25.1°c. the final tem
Vlad [161]

The heat lost by the metal should be equal to the heat gained by the water. We know that the heat capacity of water is simply 4.186 J / g °C. Therefore:

100 g * 4.186 J / g °C * (31°C – 25.1°C) = 28.2 g * Cp * (95.2°C - 31°C)

<span>Cp = 1.36 J / g °C</span>

4 0
3 years ago
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