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3 years ago

With the exception of our sun, most stars are huge, bright balls of gas located trillions of miles away from earth true or false

Chemistry

2 answers:

Ivenika [448]3 years ago

3 0

Answer:

True

Explanation:

Stars are bright and enormous astronomical bodies that are located at a large distance from the earth. They are made up of the lightest gaseous elements namely hydrogen and helium. These hydrogen atoms undergo the reaction of nuclear fusion, which fuels the energy of the star and allows the star to shine, releasing a large amount of energy. They are located about trillions of miles away from the location of the earth, due to which they appear smaller in size.

Thus, the above-given statement is True.

max2010maxim [7]3 years ago

3 0

Answer:

True

Explanation:

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Calcium carbide reacts with water to produce acetylene gas according to the following equation: CaC2(s) + 2H2O(l)C2H2(g) + Ca(OH

poizon [28]

Answer:

33.7

Explanation:

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3 years ago

Which scientist was the first to devise the rules of chemical reactions that are explained by modern atomic theory?

valina [46]

Answer:

John Dalton is the correct answer.

Explanation:

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3 years ago

Use the reaction given below to solve the problem that follows: Calculate the mass in grams of aluminum oxide produced by the re

bearhunter [10]

Answer: 28.4 g of aluminum oxide is produced by the reaction of 15.0 g of aluminum metal

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}$

$\text{Moles of} Al=\frac{15.0g}{27g/mol}=0.556moles$

The balanced chemical equuation is:

$4Al+3O_2\rightarrow 2Al_2O_3$

According to stoichiometry :

4 moles of $Al$ produce == 2 moles of $Al_2O_3$

Thus 0.556 moles of $Al$ will produce= $\frac{2}{4}\times 0.556=0.278moles$ of $Al_2O_3$

Mass of $Al_2O_3=moles\times {\text {Molar mass}}=0.278moles\times 102g/mol=28.4g$

Thus 28.4 g of aluminum oxide is produced by the reaction of 15.0 g of aluminum metal.

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3 years ago

For a particular isomer of C8H18, the combustion reaction produces 5104.1 kJ of heat per mole of C8H18(g) consumed, under standa

Vladimir79 [104]

Answer:

Explanation:

Hello,

Considering the chemical reaction, the enthalpy of reaction is given by:

ΔH°rxn=ΔfHCO2+ΔfHH2O-ΔfHC8H18

(ΔfHO2=0)

Taking into account that the reaction produces energy, ΔH°rxn is negative. No, solving for ΔfHC8H18:

ΔfHC8H18=-ΔH°rxn+8*ΔfHCO2+9*ΔfHH2O

ΔfHC8H18=-(-5104.1 kJ/mol)+9*(-292.74kJ/mol)+8*(-393.5 kJ/mol)

ΔfHC8H18=-678.56 kJ/mol

Best regards.

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3 years ago

How are the isotopes of an element different from one another ?

Serggg [28]

They have the same number of protons in the nucleus, giving them the same atomic number, but a different number of neutrons giving each elemental isotope a different atomic weight.

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3 years ago