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2 years ago

An atom which has 9 protons, 8 neutrons, and 9 electrons will have an atomic mass of how many amu?

Chemistry

1 answer:

rjkz [21]2 years ago

8 0

Answer:

Explanation:

Protons and Neutrons both have a mass of about 1 amu so you add them but electrons have a mass of 0 amu so they are left out.

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If the bright lines in the spectrum of oxygen are matched by lines in the dark-line spectrum of the sun, what does that indicate

lbvjy [14]

Hello young fellow friend I think the anwser is (C)

7 0

3 years ago

Read 2 more answers

2NO + 3MnO2 + 4H â 2NO3- + 3Mn2 + 2H2O For the above redox reaction, assign oxidation numbers and use them to identify the eleme

mixer [17]

Answer:

Manganese decreases from 4+ to 2+ (reduced and oxidizing agent) and nitrogen increases from 2+ to 5+ (oxidized and reducing agent).

Explanation:

Hello there!

In this case, according to the given redox reaction, we rewrite it as a convenient first step:

$2NO + 3MnO_2 + 4H^+ \rightarrow 2NO_3^- + 3Mn^{2+} + 2H_2O$

Next, we assign the oxidation numbers as follows:

$2N^{2+}O^{2-} + 3Mn^{4+}O^{-2}_2 + 4H^+ \rightarrow 2(N^{5+}O^{2-}_3)^- + 3Mn^{2+} + 2H^+_2O^{2-}$

Thus, we can see that both manganese and nitrogen undergo a change in their oxidation number, the former decreases from 4+ to 2+ (reduced and oxidizing agent) and the latter increases from 2+ to 5+ (oxidized and reducing agent).

Regards!

4 0

2 years ago

Foods cook faster when placed in a pressure cooker. This is because the pressure on the surface of the water is (higher than/low

tia_tia [17]

Answer:

The pressure is higher than the atmospheric one, therefore the temperature is less.

Explanation:

When it is closed permanently, the pressure of the pot inside it increases, generating that the atoms and particles of the water are closer together, increasing their kinetic energy, if intermolecular friction and therefore the boiling point is lower, because the water reaches a boil or boil at a lower temperature.

5 0

2 years ago

Which statement describes a physical property of copper?

hram777 [196]

Answer:

Copper is typically a solid and has a coppery, bronzy color. It is a metal and has a relatively high melting point. It has a strong luster and can conduct electricity.

7 0

2 years ago

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What aqueous solution has the highest boiling point at standard pressure? A) 1.0 M KCl(aq) B) 1.0 M CaCl2(aq) C) 2.0 M KCl(aq) D

Lapatulllka [165]

The increase in the boiling point of a solvent is a colligative property.

That means that the increase in the boling point will be related to the number of particles (molecules or ions) present in the solution.

The higher the number of particles (molecules or ions) the higher the increase in the boiling point.

All the aqueous solutions presented are electrolytes, i.e. the solutes are ionic compounds.

Then, you have to compare the number of ions that you have in each solution.

A) 1.0 M KCl ---> 1.0 M K+ + 1.0 MCl- = 2 moles of particles / liter

B) 1.0 M CaCl2 --> 1.0M Ca(2+) + 1.0M * 2 Cl (-) = 3 moles of particle / liter

C) 2.0M KCl ---> 2.0 M K+ + 2.0 M Cl- = 4 moles of particle / liter

D) 2.0 M CaCl2 ----> 2.0 M Ca (2+) + 2.0M * 2 Cl (-) = 6 moles of particle / liter.

Then, the solution 2.0M CaCl2(aq) has the highest increase in the boiling point.

Answer: option D) 2.0 M Ca Cl2(aq)

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3 years ago