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Mkey [24]
3 years ago
10

It's Peggy Sue's birthday and she's about to blow out the candles on her cake. Brother Roger stops the party when he shouts: "Lo

ok at that! Chemical and physical changes taking places on your birthday cake!"
How would you respond to Roger?
A) Roger is incorrect. The melting wax is a physical change but there is no chemical change taking place.
B) Roger is correct. Lighting the match is a chemical change and burning the candles is a physical change.
C) Roger is correct. The melting wax is a physical change and the burning candle wick is a chemical change.
D) Roger is incorrect. Only a chemical change is taking place as evidenced by the light and heat of the burning candles.
Chemistry
2 answers:
Mandarinka [93]3 years ago
6 0

The correct answer is C). I really hope this helps yall. Plz mark me as Brainliest. :D

Charra [1.4K]3 years ago
3 0
This example is an controversial matter because melting an candle is considered as both physical change and chemical change because no new substances were made by melting an candle. The final answer is C.
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An aqueous KNO3 solution is made using 76.6 g of KNO3 diluted to a total solution volume of 1.84 L. (Assume a density of 1.05 g/
defon

Answer:

The answer to your question is Molarity = 0.41

Explanation:

Data

mass of KNO₃ = 76.6 g

volume = 1.84 l

density = 1.05 g/ml

Process

1.- Calculate the molecular mass of KNO₃

molecular mass = 39 + 14 + (16 x 3) = 101 g

2.- Calculate the number of moles

                      101 g of KNO₃  --------------- 1 mol

                       76.6 g of KNO₃ ------------  x

                        x = (76.6 x 1) / 101

                        x = 0.76 moles

3.- Calculate molarity

Molarity = \frac{number of moles}{volume}

Substitution

Molarity = \frac{0.76}{1.84}

Result

Molarity = 0.41

7 0
3 years ago
Heat that flows by conduction is the transfer of thermal energy between substances in contact. What must occur for this to happe
iragen [17]
Is this the full question?

<span>Heat that flows by conduction is the transfer of thermal energy between substances in contact. For this to happen, what must occur?

A) The two systems must be the same temperature.
B) The two systems must not be touching each another.
C) One system must have higher kinetic energy than the other system.
D) The thermal energy of one system must be the same as the thermal energy of the other system.</span>
6 0
3 years ago
Read 2 more answers
Consider the following equilibrium systems: A⇌2B ΔH o =20.0 kJ/mol Reaction 1 A+B⇌C ΔH o =−5.4 kJ/mol Reaction 2 A⇌B ΔH o =0.0 k
galina1969 [7]

Answer:

Reaction 1: Kc increases

Reaction 2: Kc decreases

Reaction 3: The is no change

Explanation:

Let us consider the following reactions:

Reaction 1: A ⇌ 2B ΔH° = 20.0 kJ/mol

Reaction 2: A + B ⇌ C ΔH° = −5.4 kJ/mol

Reaction 3: 2A⇌ B ΔH° = 0.0 kJ/mol

To predict what will happen when the temperature is raised we need to take into account Le Chatelier Principle: when a system at equilibrium suffers a perturbation, it will shift its equilibrium to counteract such perturbation. This means that <em>if the temperature is raised (perturbation), the system will react to lower the temperature.</em>

Reaction 1 is endothermic (ΔH° > 0). If the temperature is raised the system will favor the forward reaction to absorb heat and lower the temperature, thus increasing the value of Kc.

Reaction 2 is exothermic (ΔH° < 0). If the temperature is raised the system will favor the reverse reaction to absorb heat and lower the temperature, thus decreasing the value of Kc.

Reaction 3 is not endothermic nor exothermic (ΔH° = 0) so an increase in the temperature will have no effect on the equilibrium.

8 0
3 years ago
Arrange the following elements in order of increasing ionization energy
Gnoma [55]

Ionization Trend: First ionization energy will increase left to right across a period and increase bottom to top of a family (column).

A) Sr, Be, Mg are all in column 2 of the periodic table. Based on the first ionization rule above, from increasing to decreasing energy, the order is: Be, Mg, Sr

B) Bi, Cs, Ba are all in the same row of the periodic table. Based on the first ionization rule above, from increasing to decreasing energy, the order is: Bi, Ba, Cs

C) Same rule as above. Order is: Na, Al, S

8 0
3 years ago
Desclony When Fe(NO3)2 dissolves in water, what particles are present in the solution?​
Hitman42 [59]

Answer:

hjfhgjgjgjghgjgjhgjhhjh

3 0
3 years ago
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