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seraphim [82]
3 years ago
7

Why is the energy supplied by the cooker greater than that calculated ?

Chemistry
1 answer:
TEA [102]3 years ago
7 0

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

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belka [17]

Answer:

the 3rd one

Explanation:

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3 years ago
Which is/are part of the macroscopic domain of solutions and which is/are part of the microscopic domain: boiling point elevatio
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Answer:

Macroscopic domain: Boiling point elevation, Henry's law, molarity, osmosis.

Microscopic domain: Hydrogen bond, ion-dipole attraction, nonelectrolyte, solvated ion.

Explanation:

A solution is composed of a solute (in high quantity) and one or more solute, which are dissolved in it. The properties of the solution can be characterized and measured in the macroscopic domain, or the microscopic domain when it's observed in the interactions with the molecules.

Boiling point elevation: It happens because the nonvolatile solvents interact with the solute, and so it will be difficult to boil it. The boiling point is a property of all the substance, and so, it can be noticed in the macroscopic domain.

Henry's law: States that the solubilization of a gas in a liquid depends on the partial pressure of the gas and by a proportional constant. Thus, the solubility of a gas is how much moles are dissolved in the volume of the solution, and so it's part of the macroscopic domain.

Hydrogen bond: It's an intermolecular interaction that happens in polar molecules that have bonds between hydrogen and a high electronegative element (N, O, or F). So, it's part of the microscopic domain.

Ion-dipole attraction: It's also an interaction that happens between an ion and a polar compound, so it's part of the microscopic domain.

Molarity: It represents how much moles of the solute is dissolved in the solution, so it's part of the macroscopic domain.

Nonelectrolyte: An electrolyte compound is the one which dissociates or ionizes, in the solvent, and because of that the solution can conduct electricity. A nonelectrolyte doesn't have this property. Because it depends on how the ions and molecules behave in solution, it's part of the microscopic domain.

Osmosis: Is the property of the solvent to go through a membrane from a side with fewer solutes (less concentrated) to another with more solute (high concentrated). So, it depends on the total amount of the solute, and so it's part of the macroscopic domain.

Solvated ion: A solvated ion is an ion that is surrounded by another ion, or by molecules, such water. So, it's part of the microscopic domain.

7 0
3 years ago
PLS HELP!
Nadya [2.5K]

Question 1

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Question 2

The Fe(III) itself absorbs some light and gives an absorbance value for the solution. Therefore, it is necessary to blank the spectrophotometer with a Fe(III) solution prior to measurement of test solutions.

6 0
2 years ago
Which statement is true of a heterogeneous mixture but not of a
Natalka [10]

Answer:

B

Explanation:

well heterogenous mixtures are not uniformly distributed these meaning whatever components are "mixed" can be seperated easily

a example of this can be

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while Homogeneous mixture cannot be seen seperated

4 0
3 years ago
Which statements describe Rutherford’s model of the atom? Select three options.
AnnZ [28]

Answer:

Well, I cannot see the options but if I were you I would choose the one closest to this. Rutherford's model shows that an atom is mostly empty space, with electrons orbiting a fixed, positively charged nucleus in set, predictable paths.

Explanation:

Again I cannot see the options but here is what I would guess. Hope this helped and have a great day! :-)

6 0
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