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tester [92]
3 years ago
15

Which of the following observations likely describes a physical change?

Chemistry
1 answer:
Inessa05 [86]3 years ago
4 0

Answer:

The answer is evaporation

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PLEASE HELP WILL GIVE BRAINLIEST!!!
IrinaVladis [17]

Answer:

The light emitted by a light bulb is a form of radiation that occurs when the filament heats up and its thermal emission gains enough energy to move into the visible spectrum.

Explanation:

Light bulbs contain a filament which is heated up electrically. When this filament is heated up,energy in the form of heat is imparted to the electrons in the filament.

This thermal excitation of electrons ultimately leads to emission of light in the viable spectrum. This light is now radiated through a light bulb.

6 0
3 years ago
How many grams are there in 2.00 moles of copper (ii) oxide
tatuchka [14]

Answer: 159 grams

Explanation:

Copper (ii) oxide has the chemical formula CuO.

Now given that:

Mass of CuO in grams = ? (let unknown value be Z)

Number of moles = 2.00 moles

Molar mass of CuO = ?

For the molar mass of CuO: Atomic mass of Copper = 63.5g ; Oxygen = 16g

= 63.5g + 16g

= 79.5 g/mol

Apply the formula:

Number of molecules = (mass in grams/molar mass)

2.00 moles = (Z / 79.5 g/mol)

Z = 79.5 g/mol x 2.00 moles

Z = 159g

Thus, there are 159 grams in 2.00 moles of copper (ii) oxide

7 0
3 years ago
The equations given in the problem introduction can be added together to give the following reaction: overall: N2O4→2NO2 However
Murljashka [212]

Answer:

Reverse the 2 NO_2 \longrightarrow 2 NO + O_2  reaction

Explanation:

Reactions:

2 NO_2 \longrightarrow 2 NO + O_2

N_2O_4 \longrightarrow 2 NO + O_2

Overall:

N_2O_4 \longrightarrow 2 NO_2

As can be seen, in the overall reaction we have N_2O_4 in the reactants like in the second reaction and NO_2 in the products. The NO_2 is in the first reaction but as a reactant so we need to reverse that reaction:

2 NO + O_2 \longrightarrow 2 NO_2

N_2O_4 \longrightarrow 2 NO + O_2

Combining:

N_2O_4 + 2 NO + O_2\longrightarrow 2 NO + O_2 + 2 NO_2

N_2O_4 \longrightarrow 2 NO_2

4 0
3 years ago
What is the electronic structure of carbon
horsena [70]

Answer:

[He] 2s2 2p2

Explanation:

5 0
3 years ago
Use the portion of the periodic table shown below to answer the questions.
Bingel [31]

The two elements that have the same properties as sodium are potassium  and rubidium .

<h3>What is periodic table?</h3>

The periodic table is an arrangement of the elements in order of increasing atomic number.

From the list, the two elements that have the same properties as sodium are potassium  and rubidium .

Proton has an atomic number of 20 and a mass number of 40. The number of electrons is the same as the number of protons. Given that the atomic number is the number of protons present, we have 20 electrons and 20 protons.

Number of neutrons = Mass number  - Number of protons

= 40 - 20 = 20 neutrons

Learn more about periodic table:brainly.com/question/11155928

#SPJ1

4 0
2 years ago
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