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2 years ago

What is the atomic number and mass number of calcium ?

Chemistry

1 answer:

solniwko [45]2 years ago

7 0

Answer:

Calcium has an Atomic number of 20 and Atomic mass of 40.078 u

Hope this helps!

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In a small, isolated group of monkeys, a new baby is born that has gray hair. The rest of the monkeys are brown. This is the res

Evgen [1.6K]

Answer:

A mutation

Explanation:

Random gene mutations can occur in isolated populations.

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2 years ago

What important discovery did Ernest Rutherford make?

EleoNora [17]

Answer:

D if im pretty sure

Explanation:

In 1909 he began experiments that were to change the face of physics. He discovered the atomic nucleus and developed a model of the atom that was similar to the solar system.

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3 years ago

Read 2 more answers

0.556 g of a solid white acid are dissolved in water and completely neutralized by the addition of 52.38 mL of 0.396 M NaOH. Cal

Veseljchak [2.6K]

Answer:

$M_{acid}=26.804g/mol$

Explanation:

Hello,

In this case, by knowing that the used NaOH equals in moles the acid (monoprotic) as shown below, during the titration:

$n_{acid}=n_{NaOH}$

By knowing the volume and the concentration of the NaOH, one obtains:

$n_{acid}=0.05238L*0.396\frac{mol}{L}=0.0207mol$

Thus, the molar mass of the acid is computed based on the previously computed moles and the given mass as follows:

$M_{acid}=\frac{m_{acid}}{n_{acid}}=\frac{0.556g}{0.0207mol}=26.804g/mol$

Best regards.

7 0

3 years ago

Express in scientific notation. Make sure your answer has the same number of significant figures as the starting value. (6.0 x 1

Greeley [361]

I believe the correct answer from the choices listed above is the second option. The expression (6.0 x 104) (3.1 x 10-1) is equal to 1.9 x 10^4. We only have two significant figures from the starting expression that is why we rounded of the product from 1.86 to 1.9.

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3 years ago

Write the molecular formula for a compound with the possible elements C, H, N and O that exhibits a molecular ion at M

liberstina [14]

Answer:

$= \mathbf{C_3H_6O}$

Explanation:

From the given information, since the molecular mass of the ion M+ is not given;

Let's assume M+ = 58.0423

So, by applying the 13th rule;

we will need to divide the mass by 13, after dividing it;

The quotient n = no. of carbon; &

The addition of the quotient (n) with the remainder r = no. of hydrogen.

So;

$\dfrac{58}{13}= 4 \ remainder \ 6$

So;

$C_nH_{n+r} = C_4H_{4+6}$

$= C_4H_{10}$

From the given information; we have oxygen present, so since the mass of oxygen = 16, we put oxygen in the molecular formula by removing $CH_4$ . Also, since the mass is an even number then Nitrogen is 0.

So, we have:

$= \mathbf{C_3H_6O}$

6 0

2 years ago