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Aleks [24]
3 years ago
12

Which of the following is an example of a physical change ?

Chemistry
1 answer:
inessss [21]3 years ago
3 0
A. A piece of Iron being heated until it melts
Because it goes from solid to liquid.
A physical change is changing from solid to a liquid, a liquid to a gas, a gas to a liquid, a liquid to a solid, a solid to a gas, or a gas to a solid.
You might be interested in
Which statements describe molecules? Check all that apply.
maria [59]

Answer:

Molecules are made of two or more atoms

Molecules range in size

Molecules are made of atoms of the same element or different elements.

5 0
3 years ago
Read 2 more answers
A student made a copper bracelet by hammering a small copper bar into the desired shape. The bracelet has a mass of 30.1 grams a
Tcecarenko [31]
69. The student's skin was obviously warmer than the initial temperature of the bracelet. According to the second law of thermodynamics, heat transfers from a higher temperature to a lower temperature hence heat transfers from the student's skin to the bracelet warming up the bracelet. 

70. moles of copper=mass of copper/molar mass of copper
=30.1g/(63.55g/mol)= 0.4736 moles Cu

71. Delta H( heat released) = mCp(deltaT) = 30.1g(0.385 J/gK)(33-19)K = 162.23J

72. Copper is chemically less active than iron. 
7 0
4 years ago
Some students were building models of solids, liquids, and gases by gluing plastic balls to a sheet of cardboard. which of their
JulsSmile [24]
Below picture contains the given models.

Answer:
            Option-B is the correct model.

Explanation:
                   Solid is a state of matter in which the particles are closely packed, has definite volume and shape. Like liquids they don't flow, either they occupy the volume of container as that occupied by both gases and liquids. The inter-molecular forces between solid particles are very strong as compared to liquids ans gases. So, the model B has a particles very closely packed to each other.

7 0
3 years ago
Given the values of So given below in J/mol K and the values of ΔHfo given in kJ/mol, calculate the value of ΔGo in kJ for the c
Fantom [35]

Answer:

-2024 kJ

Explanation:

The combustion of propane is

C₃H₈(g) + 5O₂(g) → 3CO₂(g) + 4H₂O(g)

And, ΔG° = ΔH° - TΔS°

Where T is the temperature in K.

ΔH° = ∑n*H°f, reactants - ∑n*H°f, products

Where n is the number of moles in the stoichiometry reaction. H°f, O₂(g) = 0 because it's a substance formed by only one element.

ΔH° = [4*(-226) +3*(-398)] - [-100] = -1998 kJ

ΔS° = ∑n*S°, reactants - ∑n*S°, products

ΔS° = [4*(184) + 3*214] - [5*204 + 271] = 87 J/K = 0.087 kJ/K

So

ΔG° = -1998 - 298*0.087

ΔG° = -2024 kJ

7 0
4 years ago
Help me pls!
fredd [130]

Answer:

true

as temperatures rise, the atoms become more active; as per the opposite (meaning as temperatures drop, the atoms start to settle down) liquid is the more medium state (because the temperature rises enough for the solid to become a a liquid but not too much that the liquid evaporates and turns into a gas) have a great day/night

5 0
3 years ago
Read 2 more answers
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