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2 years ago

Choose the correct statements from the list below:

Chemistry

1 answer:

ioda2 years ago

6 0

In chemistry:
When something is oxidized, it loses electrons.
When something is reduced, it gains electrons.
So the correct statements would be the second to last and third to last statements

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What does mechanical digestion mean ?

Alex787 [66]

Answer:

Explanation:

Mechanical digestion involves physically breaking down food substances into smaller particles to more efficiently undergo chemical digestion. The role of chemical digestion is to further degrade the molecular structure of the ingested compounds by digestive enzymes into a form that is absorbable into the bloodstream.

4 0

2 years ago

Which describes a scenario in which the Doppler effect is occurring?

s2008m [1.1K]

The correct answer is option B, that is, the pitch changes from low to high.

The Doppler shift or the Doppler Effect refers to the variation in the wavelength or frequency of a wave in association with an observer who is traveling comparative to the source of the wave. A prime illustration of Doppler shift is the modification of the pitch heard when a vehicle sounding a horn comes towards and move away from an observer.

In comparison to the frequency emitted, the obtained frequency is greater at the time of approach, similar at the instant of passing by, and lower at the time of recession.

8 0

2 years ago

Read 2 more answers

Hydrogen fluoride is used in the manufacture of Freons (which destroy ozone in the stratosphere) and in the production of alumin

Lerok [7]

<u>Answer:</u> The percentage yield of HF is 73.36 %

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ....(1)

For calcium fluoride:

Given mass of calcium fluoride = 6.25 kg = 6250 g (Conversion factor: 1 kg = 1000 g)

Molar mass of calcium fluoride = 78.07 g/mol

Putting values in above equation, we get:

$\text{Moles of calcium fluoride}=\frac{6250g}{78.07g/mol}=80.05mol$

For the given chemical reaction:

$CaF_2+H_2SO_4\rightarrow CaSO_4+2HF$

By Stoichiometry of the reaction:

1 mole of calcium fluoride produces 2 moles of hydrofluoric acid

So, 80.05 moles of calcium fluoride will produce = $\frac{2}{1}\times 80.05=160.1mol$ of hydrofluoric acid

Now, calculating the theoretical yield of hydrofluoric acid using equation 1, we get:

Moles of of hydrofluoric acid = 160.1 moles

Molar mass of hydrofluoric acid = 20.01 g/mol

Putting values in equation 1, we get:

$160.1mol=\frac{\text{Theoretical yield of hydrofluoric acid}}{20.01g/mol}=3203.6g=3.20kg$

To calculate the percentage yield of hydrofluoric acid, we use the equation:

$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Experimental yield of hydrofluoric acid = 2.35 kg

Theoretical yield of hydrofluoric acid = 3.20 kg

Putting values in above equation, we get:

$\%\text{ yield of hydrofluoric acid}=\frac{2.35g}{3.20g}\times 100\\\\\% \text{yield of hydrofluoric acid}=73.36\%$

Hence, the percentage yield of HF is 73.36 %

4 0

2 years ago

How many functional groups does the isopropanol contain that can experience this type of interaction

nalin [4]

Answer:

This question is incomplete

Explanation:

This question is incomplete but what you should know is that isopropanol (also referred to rubbing alcohol) has just one functional group. This functional group is called the hydroxyl group (-OH) and it's the reason the compound name ends with "ol". The hydroxyl group can be seen in the structure of the compound (Isopropanol) below

H OH H

| | |

H- C - C - C - H

| | |

H H H

If there is any functional group in isopropanol required for any form of interaction, that functional group will be the hydroxyl group because that's the only functional group isopropanol has.

NOTE: Functional group is an atom or group of atoms that determines the chemical properties of a compound.

3 0

3 years ago

What is the oxidation number of nitrogen in the nitrate ion NO3^1-

harina [27]

Answer:

Explanation:

You use the rules for oxidation numbers to calculate that the oxidation number of N is +5.

5 0

3 years ago