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2 years ago

How many elements are there

Chemistry

2 answers:

Kobotan [32]2 years ago

8 0

Explanation:

there are 118 elements.

Levart [38]2 years ago

6 0

Answer:

there r 118 elements in periodic table..

hope it helps.

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Help anyone please ;)<br> will mark brainliest!!<br> thank you lol <3

Usimov [2.4K]

Answer:

The answer to your question is below

Explanation:

2.- 6

3.- Carbon

4.- These electrons can be share to obtain stability.

5.- Protons, electrons

6.- electron cloud

7.- I and III

8.- 1

9.- 8A

10.- 4

11.- F

12.- F

13.- F

14.- T

15.- T

16.- T

17.- T

18.- T (I can not read the question but I think is true)

5 0

2 years ago

Read 2 more answers

Toluene (C6H5CH3 ), an organic compound often used as a solvent in paints, is mixed with a similar organic compound, benzene (C6

Sergeeva-Olga [200]

Explanation:

The given data is as follows.

Weight of solute = 75.8 g, Molecular weight of solute (toulene) = 92.13 g/mol, volume = 200 ml

Therefore, molarity of toulene is calculated as follows.

Molarity = $\frac{\text{weight of solute}}{\text{molecular weight of solute}} \times \frac{1000}{\text{volume of solution in ml}}$

= $\frac{75.8 g}{92.13 g/mol} \times \frac{1000}{200 ml}$

= 4.11 M

Hence, molarity of toulene is 4.11 M.

As molality is the number of moles of solute present in kg of solvent.

So, we will calculate the molality of toulene as follows.

Molality = $\frac{\text{given weight of solute}}{\text{given molecular weight of solute}} \times \frac{1000}{\text{weight of solvent in grams}}$

= $\frac{75.8 g}{92.13 g/mol} \times \frac{1000}{95.6 g}$

= 8.6 m

Hence, molality of given toulene solution is 8.6 m.

Now, calculate the number of moles of toulene as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{75.8 g}{92.13 g/mol}$

= 0.8227 mol

Now, no. of moles of benzene will be as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{95.6 g}{78.11 g/mol}$

= 1.2239 mol

Hence, the mole fraction of toulene is as follows.

Mole fraction = $\frac{\text{moles of toulene}}{\text{total moles}}$

= $\frac{0.8227 mol}{(0.8227 + 1.2239) mol}$

= 0.402

Hence, mole fraction of toulene is 0.402.

As density of given solution is 0.857 $g/cm^{3}$ so, we will calculate the mass of solution as follows.

Density = $\frac{mass}{volume}$

0.857 $g/cm^{3}$ = $\frac{mass}{200 ml}$ (As 1 $cm^{3}$ = 1 g)

mass = 171.4 g

Therefore, calculate the mass percent of toulene as follows.

Mass % = $\frac{\text{mass of solute}}{\text{mass of solution}} \times 100$

= $\frac{75.8 g}{171.4 g} \times 100$

= 44.22%

Therefore, mass percent of toulene is 44.22%.

8 0

3 years ago

What phase of matter is oxygen at room temperature

Vedmedyk [2.9K]

Gas

good luck mate :)

8 0

2 years ago

A solution of ammonia has a pH of 11.8. What is the concentration of OH– ions in the solution?

balu736 [363]

PH + pOH = 14

11.8 + pOH = 14

pOH = 14 - 11.8

pOH = 2.2

[OH-] = 10 ^- pOH

[OH-] = 10 ^- 2.2

[OH-] = <span>6.33 x 10^-3 M
</span>
Answer B

hope this helps!

3 0

2 years ago

Read 2 more answers

1. What is the molarity of a solution which contains 0.256 mol of a substance dissolved in 143 mL of solution.

LenaWriter [7]

Answer:

The equation for molarity is moles/liter for the first question you would do 0.256/0.143 liters to get 1.790 mol/L

Explanation:

The second problem you would do need to find the moles of NaCl which you would do by doing 4.89 g/58.44g/mol= 0.08367 then do 0.08367/0.600= 0.139 mol/L

The third problem would be the same steps as the second one.

The fourth problem would be (0.460M)(5.50L)= 2.53 moles

4 0

2 years ago

How many elements are there​

How many elements are there