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2 years ago

When you blow dry your hair

2 answers:

4 0

Any change that occurs without altering the chemical composition of a substance is a physical change. Physical changes can include changing the color, shape, state of matter, or volume of a substance
A usually irreversible chemical reaction involving the rearrangement of the atoms of one or more substances and a change in their chemical properties or composition, resulting in the formation of at least one new substance: The formation of rust on iron is a chemical change.

The answers to the questions are :
Physical
Chemical
Chemical
Chemical
Chemical
Chemical

mixer [17]2 years ago

3 0

In short a physical change is something that changed the way something looks but doesn't affect the chemical makeup. Drying your hair doesn't change the color of your hair, it just makes it dry so thats a physical change. Rust forming on a knife is a chemical change becaause the water reacts with the chemical makeup of the knife. Hope that helps.

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Explain what it means to be considered a “renewable” energy source, and what it means to be a “non-renewable” energy source.

Neporo4naja [7]

Answer: Resources are characterized as renewable or nonrenewable

- a renewable resource can replenish itself at the rate it is used such as solar energy, wind energy, hydro energy, and tidal energy.

- a nonrenewable resource has a limited supply such as coal, gas, nuclear energy, and fossil fuels.

3 0

2 years ago

At a certain temperature the vapor pressure of pure thiophene is measured to be . Suppose a solution is prepared by mixing of th

Lesechka [4]

Answer:

0.35 atm

Explanation:

It seems the question is incomplete. But an internet search shows me these values for the question:

" At a certain temperature the vapor pressure of pure thiophene (C₄H₄S) is measured to be 0.60 atm. Suppose a solution is prepared by mixing 137. g of thiophene and 111. g of heptane (C₇H₁₆). Calculate the partial pressure of thiophene vapor above this solution. Be sure your answer has the correct number of significant digits. Note for advanced students: you may assume the solution is ideal."

Keep in mind that if the values in your question are different, your answer will be different too. However the methodology will remain the same.

First we calculate the moles of thiophene and heptane, using their molar mass:

137 g thiophene ÷ 84.14 g/mol = 1.63 moles thiophene

111 g heptane ÷ 100 g/mol = 1.11 moles heptane

Total number of moles = 1.63 + 1.11 = 2.74 moles

The mole fraction of thiophene is:

1.63 / 2.74 = 0.59

Finally, the partial pressure of thiophene vapor is:

Partial pressure = Mole Fraction * Vapor pressure of Pure Thiophene

Partial Pressure = 0.59 * 0.60 atm

Pp = 0.35 atm

3 0

3 years ago

Hydrogen gas is collected over water at 21 degrees Celsius. At 21 degrees Celsius the vapor pressure of water is 18.7 torr. If t

Alinara [238K]

Answer : The pressure of hydrogen gas is, 739.3 torr

Explanation :

As we are given:

Vapor pressure of water = 18.7 torr

Barometric pressure = 758 torr

Now we have to calculate the pressure of hydrogen gas.

Pressure of hydrogen gas = Barometric pressure - Vapor pressure of water

Pressure of hydrogen gas = 758 torr - 18.7 torr

Pressure of hydrogen gas = 739.3 torr

Therefore, the pressure of hydrogen gas is, 739.3 torr

3 0

3 years ago

What are the main properties of liquids (in contrast to gases and solids)? check all that apply. check all that apply. liquids h

saw5 [17]

B is true because liquids are still more compact than gases, although they are loose, they aren't completely free. They also don't have a definite volume, making them assume the shape of their container. As for compression, liquids are harder to compress compared to gases.

5 0

3 years ago

Which of these solutes raises the boiling point of water the most?

sergey [27]

Answer:

D. ionic sodium phosphate (Na3PO4)

Explanation:

Molecule for molecule, the solute that raises the boiling point of water the most is the one that makes the most particles in the solution. Lithium chloride breaks up into two ions (Li+ and Cl-). So does sodium chloride (Na+ and Cl-). Molecular molecules don't break up at all, so sucrose has only 1 particle per molecule. Sodium phosphate makes 4 total particles (3 Na+ ions and 1 PO4^3-). And magnesium bromide would make 3 particles (1 Mg2+ and 2 Br-). So the most is 4.

6 0

3 years ago