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JulsSmile [24]
2 years ago
8

Which of these are physical changes in matter? Check all that apply boiling water a pencil being sharpened exploding dynamite fr

eezing water rotting cheese
Chemistry
2 answers:
AveGali [126]2 years ago
4 0

Answer: Boiling water, pencil being sharpened, freezing water.

Explanation: Physical change is the change in which there is no rearrangement of atoms and there is change in size or shape of the substance.

Chemical change is the change in which there is rearrangement of atoms and the new substances get formed.

Boiling water only changes the phase from liquid to gas and thus is a physical change.

Pencil on being sharpened only gets smaller in size and thus is a physical change.

exploding dynamite would result into formation of new substances and hence a chemical change.

Freezing water only changes the phase from liquid to solid and thus is a physical change.

Rotting cheese would result in formation of new substances and hence a chemical change.

Vlad [161]2 years ago
3 0

Explanation:

A change that does not lead to any difference in chemical composition of a substance is known as a physical change.

For example, shape, size, mass, volume, density, boiling point, etc of a substance are all physical properties.

On the other hand, changes that lead to bring change in chemical composition of a substance is known as a chemical change.

For example, exploding dynamite, rotting cheese etc are all chemical changes.

Thus, we can conclude that following are the physical changes in matter.

  • boiling water.
  • a pencil being sharpened.
  • freezing water.
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A metal, M , of atomic mass 56 amu reacts with chlorine to form a salt that can be represented as MClx. A boiling point elevatio
Goryan [66]

Answer:

  MCl₂

Explanation:

The formula for boiling point elevation can be used to find x. The "complete dissociation" means there will be an ion of M and x ions of Cl in the solution. The number of moles of solute will be 30.2 grams divided by the molecular weight of MClx, where x is the variable we're trying to find.

  \Delta T=imK_b\qquad\text{where i=ions/mole, m=molality, $K_b\approx 0.512$}\\\\376.81-373.15=(x+1)\dfrac{\text{moles}}{\text{kg solvent}}(0.512)\\\\\dfrac{3.66}{0.512}=(x+1)\dfrac{\dfrac{30.2}{56+35.45x}}{0.1}=\dfrac{302(x+1)}{56+35.45x}\\\\\dfrac{3.66}{0.512\cdot 302}(56+35.45x)=x+1\\\\\dfrac{3.66\cdot 56}{0.512\cdot 302}-1=x\left(1-\dfrac{3.66\cdot 35.45}{0.512\cdot 302}\right)\\\\x=\dfrac{50.336}{24.877}\approx 2.023

Then the formula for the salt is MCl₂.

6 0
2 years ago
The common constituent in all acid solutions is
Oksi-84 [34.3K]

Answer:

H+/H3O , H2O

Explanation:

The ability to be a proton donor is the Bronsted-Lowry definition of acids. The Lewis definition of an acid is an electron pair acceptor, which covers molecules liKE BF3

The ability to accept a pair of electrons is what is common to all acids, not the ability to be a proton donor.

All acid solutions contain hydronium ions (H3O+), hydroxide ions (OH-) and water molecules. Each different acid solution will then have an anion that is exclusive to that acid. For example, hydrochloric acid solution will contain all of the above and chloride ions (Cl-).

All acids contain the acidic substance dissolved in water. Water naturally dissociates to a small amount, creating hydronium and hydroxide ions. But most of the water remains as water molecules.

Then when we add an acid, like HCl, the oxygen on the water attracts the hydrogen from the HCl. The electrons in the covalent bond remain with the chlorine, giving it a negative charge and thus it becomes the chloride ion (Cl-). The hydrogen now has a positive charge and as said before, is attracted to the water (specifically the lone pair of electrons on the oxygen) to create hydronium ions.

This creates extra hydronium ions, making the solution acidic. But remember, there are still water molecules, hydroxide ions and the negative ion all in solution for all acids.

8 0
2 years ago
Jill is doing an experiment on the movement of pill bugs. She will place the pill bugs on flat surfaces covered with diffirent m
Ostrovityanka [42]

Answer:D

Explanation:

6 0
2 years ago
By mistake, a quart of oil was dumped into a swimming pool that measures 25.0 m by 30.0 m. The density of the oil was 0.750 g/cm
kondor19780726 [428]

The oil slick thick = 1.256 x 10⁻⁴ cm

<h3>Further explanation</h3>

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The unit of volume can be expressed in liters or milliliters or cubic meters

The conversion is

1 cc = 1 cm3

1 dm = 1 Liter

1 L = 1.06 quart

<em>so for 1 quart = 0.943 L</em>

\tt 0.943~L=0.943\times 10^{-3}m^3

Volume of oil dumped = volume of swimming pool

\tt 0.943\times 10^{-3}~m^3=25\times 30\times h(h=thick)\\\\h=\dfrac{0.943\times 10^{-3}}{750~m^2}=1.257\times 10^{-6}~m=\boxed{\bold{1.256\times 10^{-4}~cm}}

3 0
2 years ago
To 100.0 g water at 25.00 ºc in a well-insulated container is added a block of aluminum initially at 100.0 ºc. the temperature o
11111nata11111 [884]
When the amount of heat gained = the amount of heat loss

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∴( M * C * ΔT )W = (M*C*ΔT) Al

when Mw is the mass of water = 100 g 

and C the specific heat capacity of water = 4.18

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and ΔT the change in temperature for Al = 100-28= 72°C

and M Al is the mass of Al block

C is the specific heat capacity of the block = 0.9 

so by substitution:

100 g * 4.18*3 = M Al * 0.9*72

∴ the mass of Al block is = 100 g *4.18 / 0.9*72

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4 0
2 years ago
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