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Rina8888 [55]
2 years ago
6

Perspex and polythene are two examples of what?​

Chemistry
1 answer:
erma4kov [3.2K]2 years ago
3 0
Perspex and polythene are good examples of insulators.
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A 33.69 g sample of a substance is initially at 29.4 °c. after absorbing 1623 j of heat, the temperature of the substance is 110
Sliva [168]
Q= mcΔT
1623 = 33.69g x c x (110.8 - 29.4)
1623 = 2742.366 g•°C x c
c = 0.59j/g•°C
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3 years ago
What point A on the phase diagram called?
Mariana [72]

Answer:

D) the critical point

Explanation:

Point A is the critical point in phase diagram. This is the highest temperature and pressure at which a pure material can exist in vapor/liquid equilibrium. Pretty cool!

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Which of the following best explain how Earth's rotation affects direction of sunrise?
lozanna [386]
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Answer:

The answer for this selection is 4

Explanation:

7 0
2 years ago
The standard heats of formation for CO2(g), C2H6(g), and H2O(l) are -394.0 kJ/mol, -84.00 kJ/mol, and -286.0 kJ, respectively. W
Ivanshal [37]

Answer:

ΔH°r = -1562 kJ

Explanation:

Let's consider the following combustion.

C₂H₆(g) + 7/2 O₂(g) ⇒ 2 CO₂(g) + 3 H₂O(l)

We can calculate the standard heat of reaction (ΔH°r) using the following expression:

ΔH°r = ∑np × ΔH°f(p) - ∑nr × ΔH°f(r)

where,

ni are the moles of reactants and products

ΔH°f(i) are the standard heats of formation of reactants and products

The standard heat of formation of simple substances in their most stable state is zero. That means that ΔH°f(O₂(g)) = 0

ΔH°r = ∑np × ΔH°f(p) - ∑nr × ΔH°f(r)

ΔH°r = [2 mol × ΔH°f(CO₂) + 3 mol × ΔH°f(H₂O)] - [1 mol × ΔH°f(C₂H₆) + 7/2 mol × ΔH°f(O₂)]

ΔH°r = [2 mol × (-394.0 kJ/mol) + 3 mol × (-286.0 kJ/mol)] - [1 mol × (-84.00 kJ/mol) + 7/2 mol × 0]

ΔH°r = -1562 kJ

6 0
3 years ago
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