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3 years ago

Explain using the particle theory why objects generally expand when heated and contract when cooled?

1 answer:

4 0

When heated, particles vibrate faster, thus increasing the distance between one another. The distance between these particles results in changes of state. Therefore, increased molecular motion results in expansion of an object. This works vice versa for cooling. As the vibrations slow down, the particles become closer together. This results in contraction.

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An electron moved from a higher energy level to a lower energy level. What most likely happened during the transition? (4 points

Alex787 [66]

Answer: The anwser is A a photon was realeased please mark brainliest

Explanation:

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2 years ago

Read 2 more answers

Select all that apply. Catalysts can save money by essentially lowering the:

k0ka [10]

Answer: Options (a) and (d) are the correct answer.

Explanation:

A catalyst is the substance which helps in increasing the rate of reaction.

Activation energy is the minimum amount of energy required by reactants to start the reaction. On addition of catalyst, the path of reaction changes because the energy barrier gap reduces and hence, the activation energy also decreases.

In the absence of catalyst, we need to increase the temperature so that reaction can occur quickly.

Whereas on addition of catalyst, there is no need to increase the temperature as the catalyst itself is sufficient to increase the rate of reaction. As a result, temperature should be lowered when there is addition of catalyst in the reaction.

Thus, we can conclude that catalysts can save money by essentially lowering the activation energy and temperature required.

4 0

3 years ago

Read 2 more answers

If a gas furnace releases 420 kcal of heat energy, what is the energy in kilojoules? (1 cal = 4.184 J)

Igoryamba

Answer:
The furnace releases 1757280 J

Explanation:
We will do the conversion on two steps:
1- convert the kcal to cal
2- convert the cal to J

Step 1: converting kcal to cal
1 kcal is equivalent to 1000 cal. Therefore:
420 kcal is equivalent to 420*1000 = 420000 cal

Step 2: converting cal to J
We are given that:
<span>1 cal = 4.184 J
</span>Therefore:
420000 cal is equivalent to 420000 * 4.184 = 1757280 J

Hope this helps :)

8 0

3 years ago

A sample of a compound contains 41.33 g of carbon and 8.67 g of hydrogen. The molar mass of the

mihalych1998 [28]

Answer:

C6H15

Explanation:

First, we calculate the empirical formula as follows:

C = 41.33 g

H = 8.67 g

We convert each mass value to mole by dividing each element by its molar mass (C = 12g/mol, H = 1g/mol)

C = 41.33g ÷ 12g/mol = 3.44mol

H = 8.67g ÷ 1g/mol = 8.67mol

Next, we divide each mole value by the smallest (3.44mol)

C = 3.44mol ÷ 3.44mol = 1

H = 8.67mol ÷ 3.44mol = 2.52

We multiply this ratio by 2 to get a simple whole number ratio

C = 1 × 2 = 2

H = 2.52 × 2 = 5.04

Based on this, the whole number ratio of C and H is 2:5, hence, the empirical formula is C2H5.

The molecular mass of the compound is given as 87.18 g/mol, hence, the molecular formula is calculated as follows:

(C2H5)n = 87.18

[12(2) + 1(5)]n = 87.18

[24 + 5]n = 87.18

(29)n = 87.18

n = 87.18 ÷ 29

n = 3.006

Approximately to whole number, n = 3

Hence, the molecular formula of the compound is [C2H5]3

= C6H15

4 0

2 years ago

Non-living factors in an ecosystem are ______.

mash [69]

Answer:

B. abiotic

Explanation:

in biology and ecology, abiotic components or abiotic factors are non living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems.

5 0

2 years ago