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kvv77 [185]
2 years ago
15

Can I have some help please

Chemistry
1 answer:
KonstantinChe [14]2 years ago
6 0
He can help you via watzapp
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Mercury has a density of 13.6 grams/mL, what is this density in cg/L?
Firdavs [7]
It would be 4.6cgL not sure tho because I didint do that good in this
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2 years ago
Why is the energy supplied by the cooker greater than that calculated ?
TEA [102]

Answer:

Explanation:

Q1.

(a) 46 200

accept 46 000

allow 1 mark for correct substitution

ie 0.5 × 4200 × 22 provided no subsequent step

2

(b) Energy is used to heat the kettle.

[3]

Q2.

(a) (approximate same size particles as each other and as liquid and gas) touching

do not accept particles that overlap

regular arrangement (filling the square)

(b) condensing

(c) solid

(d) physical

(e) particles have more kinetic energy

particles move faster

(f) mass of the liquid

specific latent heat of evaporation

(g) 2 × 4 200 × 801

672 000 (J)

an answer of 672 000 (J) scores 2 marks

[11]

Q3.

(a) x-axis labelled and suitable scale

Page 12 of 13

points plotted correctly

allow 5 correctly plotted for 2 marks, 3−4

correctly plotted for 1 mark

allow ± ½ square

2

line of best fit

(b)

allow ecf from line of best fit in part (a)

0.075 (°C/s)

an answer of 0.075 (°C/s) scores 2 marks

(c) Δθ = 11.5 (°C)

a calculation using an incorrect temperature

scores max 3 marks

ΔE = 1.50 × 900 × 11.5

ΔE = 15 525 (J)

ΔE = 15.525 (kJ)

an answer of 15.525 (kJ) or 15.53 (kJ) or 15.5

(kJ) scores 4 marks

an answer of 15 525 (kJ) scores 3 marks

[10]

Q4.

(a) 80 °C

ΔE = 0.5 × 3400 × 80

ΔE = 136 000 (J)

an answer of 136 000 (J) scores 3 marks

(b) energy is dissipated into the surroundings

allow any correct description of wasted energy

(c) put a lid on the pan

allow any sensible practical suggestion

eg add salt to the water

Page 13 of 13

(d) efficiency = 300/500

efficiency = 0.6

an answer of 0.6 or 60% scores 2 marks

allow efficiency = 60%

an answer of 0.6 with a unit scores 1 mark

an answer of 60 without a unit scores 1 mark

7 0
2 years ago
An atom has eight protons and nine neutrons. draw the atomic structure of the atom
Cloud [144]
Draw eight circles and nine more in a big circle = this represents your nucleus
draw eight electrons (since electrons = protons in neutral elements) outside of it (2 in one ring, then 6 in a second ring)
7 0
2 years ago
Aluminum reacts with chlorine gas to produce aluminum chloride according to the following equation. Al + Cl2 → AlCl3 Which of th
anzhelika [568]
<h3><u>Answer</u>;</h3>

B. 3/2

<h3><u>  Explanation;</u></h3>

Balance the chemical equation

2Al + 3Cl2 → 2AlCl3

We want to convert moles of AlCl3 to moles of Cl2

The conversion factor is 2 mol AlCl3/3 mol Cl2.

We choose the one that makes the units cancel:

x mol AlCl3 x (3 mol Cl3)/(2mol AlCl3) = x mol Al

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4 0
3 years ago
Read 2 more answers
how much hydrogen will be released during the interaction of potassium weighing 8 grams with hydrochloric acid
krek1111 [17]

Answer:

With an understanding of the ideal gas laws, it is now possible to apply these principles to chemical stoichiometry problems. For example, zinc metal and hydrochloric acid (hydrogen chloride dissolved in water) react to form zinc (II) chloride and hydrogen gas according to the equation shown below:

2 HCl (aq) + Zn (s) → ZnCl2 (aq) + H2 (g)

Explanation:

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