Chemistry explain it and if you can show the worki need with both of the questions

Question 3.

They are equal in magnitude but opposite in sign.

Explanation:

Fusion is another word for melting and crystallization is another word for freezing.

They are opposite processes, so the heat you must add (positive sign) to melt a substance is equal to the heat released but with a negative sign.

ΔH(fus) = -ΔH(cryst)

Question 4.

18 400 J

Explanation:

There are two heat transfers in this question.

Total heat = heat to cool water + heat to freeze water

      q         =               q₁              +                q₂

      q         =            mCΔT          +        mΔH(freeze)

Calculate q₁

m = 40.0 g

C = 4.184 J·K⁻¹g⁻¹

ΔT = T_f – T_i = 0 °C - 30 °C = -30 °C

q₁ = 40.0 × 4.184× (-30)

q₁ = -5020 J

Calculate q₂

ΔH(cryst) = -334 J·g⁻¹

q₂ = 40.0 × (-334)

q₂ = -13 360 J

Calculate the total heat

q = -5 020 – 13 360

q = - 18 400 J

The negative sign shows that heat is removed, so you must remove

18 400 J.

the mass of the cathode increases because ions from the solution get reduced to atoms and become part of the cathode.

explanation:

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stan bts

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance