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Reika [66]
3 years ago
9

What is the mass number of an atom that has 12 neutrons and 11 protons?

Chemistry
2 answers:
TiliK225 [7]3 years ago
8 0

Answer:

23

Explanation:

Tamiku [17]3 years ago
5 0
Mass number = protons + neutrons. 12 + 11 = 23.
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When sodium peroxide is added to water, sodium hydroxide and oxygen gas is produced.
lukranit [14]

Answer:

The reaction combines the sodium with the hydrogen and oxygen in water to form sodium hydroxide and hydrogen gas, and you get a lot of energy released as heat as well. This heat actually melts any remaining sodium that has not reacted yet, and ignites the hydrogen gas, so you get the bang and the flash.

Explanation:

8 0
2 years ago
To determine the freezing point depression of a LiCl solution, Toni adds 0.411 g of LiCl to the sample test tube along with 19.7
Cerrena [4.2K]

Answer:

LiCl = 0.492 m

Explanation:

Molal concentration is the one that indicates the moles of solute that are contained in 1kg of solvent.

Our solute is lithium chloride, LiCl.

Our solvent is distilled water.

We do not have the mass of water, but we know the volume, so we should apply density to determine mass.

Density = mass / volume

Density . volume = mass

1 g/mL . 19.7 mL = 19.7 g

We convert g to kg → 19.7 g . 1 kg / 1000g = 0.0197 kg

Let's determine the moles of LiCl

0.411 g . 1 mol / 42.394 g = 9.69×10⁻³ moles

Molal concentration (m) = 9.69×10⁻³ mol / 0.0197 kg → 0.492 m

7 0
2 years ago
UNIT TEST
Aleksandr-060686 [28]

Answer:

Six

Explanation:

I just took it and that is the correct answer.

8 0
2 years ago
Answer these questions based on 234. 04360 as the atomic mass of thorium-234. The masses for the subatomic particles are given.
nikdorinn [45]

The mass defect for the isotope thorium-234 if given mass is 234.04360 amu is 1.85864 amu.

<h3>How do we calculate atomic mass?</h3>

Atomic mass (A) of any atom will be calculated as:

A = mass of protons + mass of neutrons

In the Thorium-234:

Number of protons = 90

Number of neutrons = 144

Mass of one proton = 1.00728 amu

Mass of one neutron = 1.00866 amu

Mass of thorium-234 = 90(1.00728) + 144(1.00866)

Mass of thorium-234 = 90.6552 + 145.24704 = 235.90224 amu

Given mass of thorium-234 = 234.04360 amu

Mass defect = 235.90224 - 234.04360 = 1.85864 amu

Hence required value is 1.85864 amu.

To know more about Atomic mass (A), visit the below link:

brainly.com/question/801533

4 0
1 year ago
Which of the following factors can be changed for a gas without changing the mass of the gas? Select all that apply.
viva [34]
It is either
volume or pressure
8 0
3 years ago
Read 2 more answers
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