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3 years ago

Which of the following isotopes has the same number of neutrons as phosphorus – 21 (atomic number 15)

1 answer:

3 0

The number of neutrons in phosphorus-21 is 16 (21-15).

Therefore the answer is B. Sulfur-32 also has 16 neutrons (32-16).

Hope this helps :)

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The ion with a +3 charge 28 electrons and mass number of 71

Talja [164]

Answer:

Good luck!

Explanation:

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3 years ago

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Which substance has a mass is 13.5 grams, and its volume is 5 cm 3.

solmaris [256]

Answer:

Substance is Aluminium

Explanation:

We are given;

Mass; m = 13.5 grams

Volume; V = 5 cm³

Formula for density is;

density = m/V

Density = 13.5/5

Density = 2.7 g/cm³

From the table attached, we can see that the element with a corresponding density of 2.7 is Aluminium

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3 years ago

How many moles are in 2.8x10^23 atoms of Calcium?

Zielflug [23.3K]

Answer: 1 mole ➡️ 6.022×10²³ atoms of si.

X mole ➡️ 2.8×10²⁴ atoms of si.

X = 2.8×10×10²³/6.022×10²³

= 28/6.022

= 4.65 moles.

Explanation:

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3 years ago

A solution of methanol and water has a mole fraction of water of 0.312 and a total vapor pressure of 21 torr at 39.9 degrees C.

Elan Coil [88]

Answer:

Explanation:

Given the details, we can say that

Pure methanol is a volatile solvent as the vapour pressure has a high value. This means that methanol - methanol intermolecular forces are weak in comparisson to water - water forces. When having about 30% of water in a methanol mixture, the mixture Pv decreased, showing that it is not a volatile mixture, so then there are strong intermolecular interactions between methanol - water, part of it due to the hydrogen bonds.

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3 years ago

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During lab, you measured the heat of reaction by mixing solutions of FeCl3 and NaOH.

Kobotan [32]

Explanation:

pls, refer to the above picture, i hope you will find it helpful.

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3 years ago