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4 years ago

Define exothermic reaction.

Chemistry

2 answers:

Maksim231197 [3]4 years ago

7 0

An exothermic reaction is a reaction that releases energy.

AleksandrR [38]4 years ago

4 0

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A chemical reaction in which heat is released is called exothermic reaction.

For example

CaO(s) + H2O(l) --> Ca(OH)2 (aq) + Heat

As we know that if energy needed in the bond breaking in the reactants is less than the energy released when new bonds are formed resulting in the products, the chemical reaction is of exothermic in nature.

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Convert 3.01€22 molecules of O²(a) mole of O²) ,volume at S.T.P,no of Oxygen atom. (d) mass

Marat540 [252]

Answer:

a )0.05 moles of O₂

b) 1.1207 dm³

c) 0.3× 10²³ atoms of oxygen

d) 1.6 g

Explanation:

Given data:

Number of molecules of O₂ = 3.01 × 10²² molecules

Number of moles of O₂ = ?

Volume of oxygen at ATP = ?

Number of oxygen atoms = ?

Mass of oxygen = ?

Solution:

The given problem will solve by using Avogadro number.

"It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance". The number 6.022 × 10²³ is called Avogadro number.

Moles of oxygen:

1 mole = 6.022 × 10²³ molecules

3.01 × 10²² molecules × 1 mol / 6.022 × 10²³ molecules

0.05 moles of O₂

Number of atoms of oxygen:

1 mole = 6.022 × 10²³ atoms

0.05 mol × 6.022 × 10²³ atoms /1 mol

0.3× 10²³ atoms of oxygen

Volume of oxygen:

1 mole of oxygen at STP occupy 22.414 dm³

0.05 mol × 22.414 dm³ / 1mol

1.1207 dm³

Mass of oxygen:

Mass = number of moles × molar mass

Mass = 0.05 mol × 32 g/mol

Mass = 1.6 g

8 0

3 years ago

What is the specific latent heat of fusion for a substance that takes 550 KJ to melt 14 KG at 262 K?

Arte-miy333 [17]

Answer:- The right choice is A. $3.9*10^4\frac{J}{kg}$ .

Solution:- Latent heat of fusion means the heat required to melt the solid at constant temperature means there is no change in temperature only the solid changes to liquid. So, it is a solid to liquid phase change.

$q=m*\Delta H_f_u_s$

where q is the heat required to convert solid to liquid, m is the mass and $\Delta H_f_u_s$ is the latent heat of fusion.

From given info, 550 kJ that is 550000 J of heat is required to melt 14 kg of solid at 262K temperature. Let's rearrange the equation for latent heat of fusion and plug in the values in it.

$\Delta H_f_u_s=\frac{q}{m}$

$\Delta H_f_u_s=\frac{550000J}{14kg}$

$\Delta H_f_u_s$ = $39286\frac{J}{kg}$

If we round this value to two sig figs and write in scientific notations then it becomes $3.9*10^4\frac{J}{kg}$ .

So, the right choice is A. $3.9*10^4\frac{J}{kg}$ .

5 0

3 years ago

Please help I will mark as Brainly

Elina [12.6K]

The answer is D because when a scientist publishes a book it helps other scientists and other scientists can help the scientists that publish the book.

7 0

3 years ago

Reactions cannot occur without a certain minimum amount of energy. what is this minimum amount of energy called?

Dovator [93]

This type of energy would be called reaction energy.

4 0

3 years ago

Read 2 more answers

Is it OK for people to post fake vacation pics and other fake info on social media? Why or why not? Use facts and details from t

asambeis [7]

Answer:

No, It is not okay to pretend on social media.

Explanation:

No, it is not okay for people to post fake vacation pics and other fake info on social media. This is very wrong, as -

This 'all time look good, feel good, have a happening life' approach of social media - implies showing only the positive side & not negative side of people's life. However, in real life is not a bed of roses.
Faking things out implies that pretending to be cool has become more important than sharing deep meaningful relationships, & highlights superficial desire of false popularity.
It is also harmful to people being communicated this fake image, as they might indulge into any social involvement, on the basis of unreal image of the concerned person.

3 0

3 years ago

Read 2 more answers

Define exothermic reaction.​

Define exothermic reaction.