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3 years ago

Use of chemical substance in our daily life their advantages and disadvantages

Chemistry

1 answer:

vekshin13 years ago

3 0

Answer:

Explanation:

By observing chemical reactions, we are able to understand and explain how the natural world works. Chemical reactions turn food into fuel for your body, make fireworks explode, cause food to change when it is cooked, make soap remove grime, and much more.

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What is transportation?

Mandarinka [93]

Movement from place to palce

3 0

3 years ago

Read 2 more answers

1. Show that heat flows spontaneously from high temperature to low temperature in any isolated system (hint: use entropy change

Inga [223]

Answer:

1 ) Δs ( entropy change for hot block ) = - Q / th ( -ve shows heat lost to cold block )

Δs ( entropy change for cold block ) = Q / tc

∴ Total Δs = ΔSc + ΔSh

= Q/tc - Q/th

2) ΔSdecomposition = Δh / Temp = ( 181.6 * 10^3 / 773 ) = 234.928 J/k

Explanation:

<u>1) To show that heat flows spontaneously from high temperature to low temperature </u>

example :

Pick two(2) solid metal blocks with varying temperatures ( i.e. one solid block is hot and the other solid block is cold )

Place both blocks for time (t ) in an insulated system to reduce heat loss or gain to or from the environment

Check the temperature of both blocks after time ( t ) it will be observed that both blocks will have same temperature after time t ( first law of thermodynamics )

Δs ( entropy change for hot block ) = - Q / th ( -ve shows heat lost to cold block )

Δs ( entropy change for cold block ) = Q / tc

∴ Total Δs = ΔSc + ΔSh

= Q/tc - Q/th

<u>2) Entropy change for Decomposition of mercuric oxide </u>

2HgO (s) → 2Hg(l) + O₂ (g)

Δs = positive

there is transition from solid to liquid and the melting point of mercury ( the point at which reaction will take place ) = 500⁰C

hence ΔSdecomposition = S⁻ Hg - S⁻ HgO =

Δh of reaction = 181.6 KJ

Temp = 500 + 273 = 773 k

hence ΔSdecomposition = Δh / Temp = ( 181.6 * 10^3 / 773 ) = 234.928 J/k

8 0

2 years ago

11) If you have a density of 100 kg/L,, tell me the following:

jenyasd209 [6]

The unit of mass is 'Kilogram' which is written as 'kg' and volume, v = 10 L.

<h3>Equation :</h3>

To calculate the volume

Use formula,

density = mass / volume

density = 100 kg/L

mass = 1000 kg

volume = mass / density

v = 1000/100

v = 10 L

<h3>What is density mass?</h3>

A substance, material, or object's mass density is a measure of how much mass (or how many particles) it has in relation to the volume it occupies.

To know more about volume :

brainly.com/question/1578538

#SPJ9

I understand the question you are looking for :

If you have a density of 100 kg/L, and a mass of 1000 units, tell me the following: First what are the mass units? Secondly, what is the volume?

8 0

1 year ago

Why can a liquid change to take the shape of its container but NOT expand to fill the container itself?

tiny-mole [99]

Answer: Option (C) is the correct answer.

Explanation:

Molecules in a liquid have less force of attraction as compared to solids. But liquid molecules have more force of attraction as compared to gases.

Since molecules of a gas are held together by weak Vander waal forces, therefore, they expand to fill the container whereas molecules in a liquid are not expanded in a container like gases because of more force of attraction within molecules of liquids as compared to gases.

Hence, a liquid can take the shape of container in which it is kept.

Thus, we can conclude that out of the given options, a liquid change to take the shape of its container but NOT expand to fill the container itself because the particles of a liquid are held together loosely enough to flow, but not so loose that they expand.

4 0

3 years ago

Read 2 more answers

A 1.42-g sample of a pure compound with formula m2so4 was dissolved in water and treated with an ex- cess of aqueous calcium chl

solong [7]

The reaction between $m_{2}SO_{4}$ with calcium chloride can be shown as- $m_{2}SO_{4}$ + $CaCl_{2}$ → $CaSO_{4}$ ↓+2mCl. The molecular weight of $CaSO_{4}$ is 136.14g. The weight of sulfate ion is 96.06g. The molecular weight of $m_{2}SO_{4}$ = (2×m + 96.06). From the reaction we can see that 1 mole of calcium chloride reacts with 1 moles $m_{2}SO_{4}$ to produce 1 mole of calcium sulfate. Now 1.36g of calcium sulfate is equivalent to 1.36/136.14=9.989× $10^{-3}$ moles of calcium sulfate.