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3 years ago

What is the correct answer and why?

Chemistry

1 answer:

MariettaO [177]3 years ago

7 0

A) number of neutrons in the nucleus... all isotopes of an element contain the same number of protons which is equal to that elements atomic number...
hope this helps!

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An orbital would never exist in the quantum description of an atom is

Mamont248 [21]

Hydrogen i think. the orbital of hydrogen is peculiar

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3 years ago

Brainliest if CORRECT 11

Klio2033 [76]

Answer:

Model B

Explanation:

Model A shows that light has been reflected, whereas Model B shows the light has been refracted. Light will be refracted as the light enters a more dense medium (glass), from a less dense medium (air).

This website has a really useful, thorough explanation for why this occurs:

(Check the explanation under the heading 'Explaining refraction - Higher')

https://www.bbc.co.uk/bitesize/guides/zw42ng8/revision/2

Hope this helps!

6 0

3 years ago

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An egg sinks in fresh water but it floats on salty water.why?

Sonbull [250]

The salt makes it rise and

8 0

3 years ago

What is the percentage of nitrogen, by mass, in calcium nitrate?.

SCORPION-xisa [38]

Answer:

Nitrogen = 17.07%

Explanation:

We are asked to calculate the percentage by mass of nitrogen in Ca(NO3)2.

The molar mass of calcium nitrate is 164,088 g/mol.

In this 164.088 g/mol there are 2 nitrogen atoms.

Molar mass of nitrogen = 14,0067 g/mol

% Nitrogen = molar mass of N/total molar mass of the compound

% Nitrogen =[(2 x 14.0067)/164.088]*100

% Nitrogen = 17.07%

Please mark me as brainliest if you found this answer helpful

7 0

2 years ago

A sample was prepared by mixing 18. ml of 3.00 x 10^-3 m crystal violet (cv) with 2.00 ml of 0.250 m naoh. calculate the resulti

Aleks [24]

Answer : The resulting concentrations of CV and NaOH are 0.0027 M and 0.025 M respectively.

Explanation :

Step 1 : Find moles of crystal violet and NaOH.

The molarity formula is

$Molarity = \frac{mol}{L}$

Molarity of crystal violet = $3.00 \times 10^{-3} = \frac{mol (CrystalViolet)}{L}$

The volume of crystal violet solution is 18 mL which is 0.018 L.

Moles of crystal violet = $3.00 \times 10^{-3} \times 0.018 = 5.4 \times 10^{-5}$

Moles of crystal violet = 5.4 x 10⁻⁵

Moles of NaOH = $Molarity \times L = 0.250 \times 0.00200 = 5.00 \times 10^{-4}$

Moles of NaOH = 5.00 x 10⁻⁴

Step 2 : Find total volume of the solution

The total volume of the solution after mixing NaOH and crystal violet is

0.018 L + 0.00200 = 0.020 L

Step 3 : Use molarity formula to find final concentrations

Molarity of crystal violet = $\frac{mol(CrystalViolet)}{Total Volume(L) } = \frac{5.4 \times 10^{-5}}{0.020} = 2.7 \times 10^{-3}$

Final concentration of CV = 0.0027 M

Molarity of NaOH= $\frac{mol(NaOH)}{Total Volume(L) } = \frac{5.00 \times 10^{-4}}{0.020} = 0.025 \times 10^{-3}$

NaOH is a strong base and dissociates completely as follows.

$NaOH (aq) \rightarrow Na^{+} (aq) + OH^{-} (aq)$

The mole ratio of NaOH and OH⁻ is 1:1 . Therefore the concentration of OH⁻ is same as that of NaOH.

Concentration of OH⁻ = 0.025 M

8 0

3 years ago