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HACTEHA [7]
2 years ago
7

What is the energy of an electron in the first energy level of hydrogen?

Chemistry
1 answer:
dybincka [34]2 years ago
5 0

Answer:

B

Explanation:

hydrogen it's atomic number (Z) is

recall from the formular of Energy

E = -2.178 x 10-18/Z

= -2.178 x 10-18/1

E = -2.178 x 10-18

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Explain the difference between molecule and compound
nadya68 [22]
Answer:
A molecule is a group of two or more atoms held together by chemical bonds. A compound is a substance which is formed by two or more different types of elements which are united chemically in a fixed proportion. All molecules are not compounds.

Good luck !
8 0
3 years ago
The most common source of copper (cu) is the mineral chalcopyrite (cufes2). how many kilograms of chalcopyrite must be mined to
tigry1 [53]

Answer : 0.8663 Kg of chalcopyrite must be mined to obtained 300 g of pure Cu.

Solution : Given,

Mass of Cu = 300 g

Molar mass of Cu = 63.546 g/mole

Molar mass of CuFeS_2 = 183.511 g/mole

  • First we have to calculate the moles of Cu.

\text{ Moles of Cu}=\frac{\text{ Given mass of Cu}}{\text{ Molar mass of Cu}}= \frac{300g}{63.546g/mole}=4.7209moles

The moles of Cu = 4.7209 moles

From the given chemical formula, CuFeS_2 we conclude that the each mole of compound contain one mole of Cu.

So, The moles of Cu = Moles of CuFeS_2 = 4.4209 moles

  • Now we have to calculate the mass of CuFeS_2.

Mass of CuFeS_2 = Moles of CuFeS_2 × Molar mass of CuFeS_2 = 4.4209 moles × 183.511 g/mole = 866.337 g

Mass of CuFeS_2 = 866.337 g = 0.8663 Kg         (1 Kg = 1000 g)

Therefore, 0.8663 Kg of chalcopyrite must be mined to obtained 300 g of pure Cu.


3 0
3 years ago
If 23.5 g of ammonia (NH3) is dissolved in 1.0 L of solution, what is the molarity?
r-ruslan [8.4K]

Answer:

1.38 M

Explanation:

Need to use the Molarity equation M=n/L

23.5g/ 17.031g/mol NH3 = 1.38 moles

1.38 moles/ 1.0 L = 1.38 M

4 0
2 years ago
Consider the following equilibrium reaction having gaseous reactants and products. 4HCl + O2 ⇌ 2H2O + Cl2 Which of the following
gulaghasi [49]
<h3><u>Answer</u>;</h3>

B.The rate of forward reaction increases.

<h3><u>Explanation;</u></h3>
  • Le Chatelier's principle states that changing a factor such as concentration, temperature, or pressure of a reaction at equilibrium will cause the reaction to shift in the direction that counteracts the effect of that change.
  • <em><u>Therefore, when reactants are added to a reaction at equilibrium shift when more reactants are added then the reaction shifts to the right to make more products.</u></em>
3 0
3 years ago
What is the SI base unit for length?
sp2606 [1]

The SI base unit for length is meter.

In order to make smaller measurements, you can use the centi-, milli-, micro-, etc. prefixes.

When you want to reference larger measurements, you can use the kilo-, mega-, giga- and prefixes such as those.

5 0
3 years ago
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