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3 years ago

WORTH 20 POINTS HELP PLEASE

Chemistry

1 answer:

Damm [24]3 years ago

5 0

Answer:

The answers to your questions are below

Explanation:

Physical change is when matter changes its form but is still the same substance.

Chemical change is when matter changes its composition.

iron and oxygen from rust It's a chemical change because iron and oxygen form a new compound different from the reactants.

iron is denser brightly when ignited . This is a chemical property because iron reacts with oxygen.

oil and water do not mix it's a physical change, oil and water are in touch but they do not react.

mercury melts at -39°C it's a physical property because mercury changes from solid to liquid but it still is mercury.

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A- Gases do not have mass.

finlep [7]

The answer is going to be d. hope that helped

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3 years ago

The different plants and animals in an environment. what is the answer for this meaning

Verdich [7]

Answer:

biodiversity

Explanation:

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3 years ago

What is the total number of electrons shown in this Lewis structure of carbon dioxide? A. 8 B. 12 C. 16 D. 24

krek1111 [17]

Answer is 16
carbon valence = 4
oxygen valence = 6 but carbon dioxide have 2 oxygen so = 12
12 + 4 = 16
so carbon dioxide have 16 electron

8 0

3 years ago

Identify the factors that govern the speed and direction of a reaction. Check all that apply.

Fiesta28 [93]

Answer: option B and option C

Explanation:

4 0

3 years ago

Aspirin can be prepared from salicylic acid ( C 7 H 6 O 3 CX7HX6OX3), which has a molar mass of 138.12 g/mol, and acetic anhydri

pychu [463]

Answer: The theoretical yield of aspirin is 4.14 g

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}$ $\text{Moles of salicylic acid}=\frac{3.20g}{138.12g/mol}=0.023moles$

mass of acetic anhydride = $density\times volume =1.082g/ml\times 3.71ml=4.01g$

$\text{Moles of acetic anhydride}=\frac{4.01g}{102.04g/mol}=0.039moles$

$C_9H_6O_3+C_4H_6O_3\rightarrow C_9H_8O_4+C_2H_3O_2$

According to stoichiometry :

1 mole of salycylic acid require 1 mole of acetic anhydride

Thus 0.023 moles of salycylic acid require= $\frac{1}{1}\times 0.023=0.023moles$ of acetic anhydride

Thus salycylic acid is the limiting reagent as it limits the formation of product and acetic anhydride is the excess reagent.

As 1 mole of salycylic give = 1 mole of aspirin

Thus 0.023 moles of salycylic acid give = $\frac{1}{1}\times 0.023=0.023moles$ of aspirin

Mass of aspirin = $moles\times {\text {Molar mass}}=0.023moles\times 180.15g/mol=4.14g$

Thus theoretical yield of aspirin is 4.14 g

4 0

3 years ago