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2 years ago

What is helium an example of? element compound atomic number subatomic particle

Chemistry

2 answers:

fgiga [73]2 years ago

4 0

Answer:

atomic number

Explanation:

hope this helps

Hatshy [7]2 years ago

3 0

I believe its element.

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Select all possible answers:

Dafna11 [192]

Answer:

c and d are correct

Explanation:

In A, false because in Valence Electrons, the more the valences, the more stable an atom is.

In B, false because atoms cannot readily gain or lose valence electrons as the number of valence electrons is determined by the column they are in.

In C, true because the more the valence electrons, the more the stability of an atom.

In D, true as electron placing is important and the reactivity of an atom is important.

So C and D are true!

7 0

2 years ago

Read 2 more answers

What is the potential energy of a rock with a mass of 10 kg while sitting on a cliff that is 15 m high

KonstantinChe [14]

150 hhhhhjjhhjjhhhhhjjjj

7 0

3 years ago

Which describes the earth as an open system with respect to energy?

Naddik [55]

Answer:

Explanation:

Any system within the Earth system is considered an open system. Because energy flows freely into and out of systems, all systems respond to inputs and, as a result, have outputs.

6 0

2 years ago

Aspirin sun thesis Green Chemistry and Assime the aspirin is prepared by the following reaction and that 10.09. of salicylic aci

klemol [59]

Answer: The percentage yield of aspirin is 38.02 %.

Explanation:

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

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

For salicylic acid:

Given mass of salicylic acid $(C_7H_6O_3)$ = 10.09 g

Molar mass of salicylic acid $(C_7H_6O_3)$ = 138.12 g/mol

Putting values in equation 1, we get:

$\text{Moles of salicylic acid}=\frac{10.09g}{138.12g/mol}=0.0730mol$

The chemical equation for the formation of aspirin follows:

$C_7H_6O_3+C_4H_6O_3\rightarrow C_9H_8O_4+CH_3COOH$

As, acetic anhydride is present in excess. So, it is considered as an excess reagent.

Thus, salicylic acid is a limiting reagent because it limits the formation of products.

By Stoichiometry of the reaction:

1 mole of salicylic acid produces 1 mole of aspirin.

So, 0.0730 moles of salicylic acid will produce = $\frac{1}{1}\times 0.0730=0.0730mol$ of aspirin

Now, calculating the mass of aspirin from equation 1, we get:

Molar mass of aspirin = 180.16 g/mol

Moles of aspirin = 0.073 moles

Putting values in equation 1, we get:

$0.073mol=\frac{\text{Mass of aspirin}}{180.16g/mol}\\\\\text{Mass of aspirin}=13.15g$

To calculate the percentage yield of aspirin, we use the equation:

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

Experimental yield of aspirin = 5.0 g

Theoretical yield of aspirin = 13.15 g

Putting values in above equation, we get:

$\%\text{ yield of aspirin}=\frac{5.0g}{13.15g}\times 100\\\\\% \text{yield of aspirin}=38.02\%$

Hence, the percent yield of aspirin is 38.01 %.

6 0

3 years ago

Which is correct if 15,390,000 is rounded to two significant figures?

BARSIC [14]

Answer:

Explanation:

Remark

This is one of those questions that you need the choices. You can't tell what you should enter. For example, in scientific notation, you would get 1.5*10^7.

Or you could keep it as an integer and round to two places 150,000,000,

I would pick scientific notation if you know how to use it. Otherwise use the interger format.

7 0

1 year ago

What is helium an example of? element compound atomic number subatomic particle​

What is helium an example of? element compound atomic number subatomic particle