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Inessa05 [86]
3 years ago
10

If an isotope of an element has 40 neutrons and a mass number of 79, how many electrons must it have?

Chemistry
1 answer:
34kurt3 years ago
5 0

Answer: 39 electrons

Explanation: Subtract 79 by 40 to get the atomic number (amount of protons) which is 39. The number of electrons must be the same as the number of protons if it's not an ionic compound so the amount of electrons is the same amount of protons.

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Suzy uses an italian salad dressing on her lunch. This ____________ mixture is a suspension of oil and vinegar. Question 19 opti
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This <u>heterogeneous </u>mixture is a suspension of oil and vinegar

A mixture is a physical combination of two or more substances and each of these substances preserves its identity and form in the mixture.

A homogeneous mixture is a mixture in which is one substance thoroughly dissolves in the other and its composition is uniform throughout the solution. e.g salt and water.

A heterogeneous mixture is one in the two substances form two layers and their composition varies throughout the mixture.

From the given information, the mixture of oil and vinegar is an example of a heterogeneous mixture.

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8 0
3 years ago
Calculate each of the following quantities:<br> (a) Total number of ions in 38.1 g of SrF₂
adelina 88 [10]

The total number of ions in 38.1 g of SrF₂ is 5.479 x 10²³.

<h3>What are ions?</h3>

Ions are the elements with a charge on them. It happens when they share electrons with other atoms to form a compound.

We have to calculate the total number of ions in 38.1 g of .

The molar mass of SrF₂ = 125.62 g/mol

The number of moles = 38.1 g of  1.0 mol / 125.62  = 0.30329 moles

Given that, total moles of SrF₂ ions in  = 1.0 mol of + 2.0 moles of  = 3.0 moles

Total moles of ions in 0.30329 moles of

= (0.30329 moles of SrF₂) x 3.0 / 1.0  = 0.90988 mol ions

We know that,

1.0 mole of ions = 6.023 x 10²³ ions

Thus, the number of total ions = ( 0.90988 mol ions) x  6.023 x 10²³ / 1.0 mol = 5.479 x 10²³ ions

Thus, the number of ions is in 38.1 g of 5.479 x 10²³ ions

To learn more about ions, refer to the link:

brainly.com/question/14295820

#SPJ4

8 0
1 year ago
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