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3 years ago

Which statements describe properties of stars? Check all that apply

Chemistry

2 answers:

blondinia [14]3 years ago

6 0

The following statements describes properties of stars;

Stars produce energy through nuclear fusion.
Stars are massive objects composed of gas.

Stars are composed primarily of hydrogen and helium

Explanation:

Stars mainly burn hydrogen gas in their core by fusion to produce the enormous energy they produce. Due to the immense gravity form their mass, stars are able to compress hydrogen gas in their core such that the atoms of the gas fuse to form heavier elements like helium. In the process, high energy is released such as in the form of electromagnetic radiation and neutrons. If the star is even bigger (supermassive stars), they are able to fuse helium into carbon dioxide producing even more fusion energy. Therefore, starts are mainly enormous blobs of burning gases.

Learn More:

For more on fusion in stars check out;

brainly.com/question/10811772

brainly.com/question/3035475

#LearnWithBrainly

7nadin3 [17]3 years ago

5 0

Answer:

A C and E

Explanation:

I took the test

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2 years ago

1) The heat of combustion for the gases hydrogen, methane and ethane are −285.8, −890.4 and −1559.9 kJ/mol respectively at 298K.

Morgarella [4.7K]

Answer:

The enthalpy of the reaction is 64.9 kJ/mol.

Explanation:

$H_2 + \frac{1}{2}O_2\rightarrow H_2O,\Delta H_1 =-285.8 kJ$ ..[1]

$CH_4 + 2O_2\rightarrow CO_2 + 2H_2O,\Delta H_2 =-890.4 kJ$ ..[2]

$C_2H_6 + \frac{7}{2}O_2\rightarrow 2CO_2 + 3H_2O,\Delta H_3= -1559.9 kJ$ ..[3]

$2CH_4(g)\rightarrow C_2H_6(g) + H_2(g),\Delta H_4=?$ ..[4]

2 × [2] - [1]- [3] = [4] (Using Hess's law)

$\Delta H_4=2\times \Delta H_2 -\Delta H_1 -\Delta H_3$

$\Delta H_4=2\times (-890.4 kJ)-(-285.8 kJ) -(-1559.9 kJ)$

$\Delta H_4=64.9 kJ/mol$

The enthalpy of the reaction is 64.9 kJ/mol.

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2 years ago

A gas is initially at a pressure of 225 kPa and a temperature of 245 K in a container that is 4.5 L. If the gas is compressed to

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2 years ago