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vivado [14]
3 years ago
13

3. Why does å star begin shining?

Chemistry
2 answers:
steposvetlana [31]3 years ago
8 0

Answer:

a star shines due to thermonuclear fusion

Explanation:

Nimfa-mama [501]3 years ago
8 0

Answer:

If heated and intense enough nuclear fusion is in the center of the star will continue. It takes a star the size of our sun about 20 million years to reach this point. Once it starts nuclear fusion, the star can shine for about 10 billion years.

Explanation:

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Assume that a daily diet of 2000 calories (i.e. 8.37 x 106 J) is converted completely to body heat.
slava [35]

Answer:

(a) the mass of the water is 3704 g

(b) the mass of the water is 199, 285.7 g

Explanation:

Given;

Quantity of heat, H= 8.37 x 10⁶ J

Part (a) mass of water (as sweat) need to evaporate to cool that person off

Latent heat of vaporization of water, Lvap. = 2.26 x 10⁶ J/kg

H = m x Lvap.

m = \frac{H}{L._{vap}} =\frac{8.37 * 10^6.J}{2.26*10^6\ \frac{J}{kg}} = 3.704 \ kg

mass in gram ⇒ 3.704 kg x 1000g = 3704 g

Part (b) quantity of water raised from 25.0 °C to 35.0 °C by 8.37 x 10⁶ J

specific heat capacity of water, C, 4200 J/kg.°C

H = mcΔθ

where;

Δθ is the change in temperature = 35 - 25 = 10°C

m =\frac{H}{c* \delta \theta} = \frac{8.37 *10^6}{4200*10} = 199.2857 kg

mass in gram ⇒ 199.2857 kg x 1000 g = 199285.7 g

5 0
3 years ago
Both E. coli and Salmonella are single-celled organisms. They do not have a nucleus or other membrane-bound organelles. Based on
AfilCa [17]

Answer:

domain bacteria

Explanation:

Salmonella and E. coli are same in the sense that they are both bacteria,

7 0
3 years ago
The equation, DF + heat Imported Asset D + F, is an example of an endothermic reaction.
zvonat [6]
The answer is TRUE.

If the Energy is on the left, then the problem is true. If it is on the right then it would be negative, false, and considered as exothermic.

Endothermic reaction = the products are higher in energy than the reactants.
Exothermic reaction = a chemical reaction that releases energy by light or heat.
4 0
3 years ago
Read 2 more answers
Name some acids and in what and how we used them
Ne4ueva [31]

Answer:

Acid Uses

Organic acids

Citric acid As a preservative for food As a flavouring agent

Ascorbic acid (also called vitamin C) In the treatment of bone marrow and scurvy diseases

Acetic acid Added to pickles to make them sour

Explanation:

7 0
3 years ago
A sample of ice is heated continuously until it becomes a liquid, and then a gas. Its temperature is recorded throughout and a g
padilas [110]

Answer:

The answer to your question is: C. The specific latent heat of fusion

Explanation:

A. The specific latent heat of vaporization  Specific latent heat of vaporization indicates the transition from liquid to vapor, but we are not looking for this definition. This answer is wrong.

B. The specific heat indicates the amount of heat needed to increase the temperature of water 1°C, so this answer is wrong.

C. The specific latent heat of fusion . This heat indicate the transition from solid ie to liquid, so this is the right answer.

D. The internal energy measures the energy of the molecules of a substance, so this answer is wrong.

3 0
3 years ago
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