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3 years ago

10

So i have a science question i need help with: Explain why it is a good practice to leave a hot beaker to cool before washing un

der running tap water.

1 answer:

Ronch [10]3 years ago

6 0

If you do not let the pot cool, it could mold when it goes into the cold water, and end up dented

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Look at the model below. Which formula is best represented by this model?

Olenka [21]

The third answer because there are two of each atom

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2 years ago

Which of the following shows the valency of 1?

Oliga [24]

$\huge \bf༆ Answer ༄$

The element having valency of 1 is ~

Sodium (Na)

6 0

2 years ago

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Espresso Coffee House is designing a coffee mug that keeps liquids hot. The research department tested several different materia

raketka [301]

Answer:

This question is incomplete

Explanation:

This question is incomplete because the result of the described experiment would have better determined the type of scientific explanation to profer. However, the type of material that will preserve the relative hotness or temperature of the hot coffee for the longest time will be a material than can resist heat transfer. These materials tend to keep hot substances hot by not allowing the heat of the coffee to be conducted or pass through it. These materials are mostly insulators or made by placing an insulator between two heat conductors.

Generally, heat is usually transferred from a region of higher concentration to a region of lower concentration, hence when the heat is denied of this transfer, the heat will remain trapped in the "heat-donor" substance (in this case the hot coffee). Thus, the material chosen (A, B or C) will be the material that resists heat transfer the most based on the explanation above.

4 0

3 years ago

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

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Water's ________ specific heat makes it heat up and cool down slowly; this stability has helped water support life.

Valentin [98]

Answer:

high

Explanation:

8 0

2 years ago

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