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3 years ago

What is the composition of an isotope of calcium (atomic number 20)?

Chemistry

2 answers:

anzhelika [568]3 years ago

6 0

Answer:

The answer to your question is: last option.

20 protons

20 electrons

25 neutrons

Explanation:

Data

Calcium, atomic number 20

Atomic number indicates the number of protons in an element, so, if Calcium's atomic number is 20, it means that it has 20 protons.

In a neutral element, the number of protons = number of electrons, then

Calcium has 20 electrons.

Only the number of neutrons could change.

According to the previous description, the last option is correct.

beks73 [17]3 years ago

4 0

Answer:

i think c

Explanation:

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If 43.1 g of O2 and 6.8 g of CO2 are placed in a 13.7 L container at 34 degrees C, what is the mixture of gasses?

jonny [76]

Answer:

The total pressure of the gas mixture = 2.76 atm

Note: The question is not complete. The complete question is as follow:

If 43.1 g of O2 and 6.8 g of CO2 are placed in a 13.7 L container at 34 degree Celsius , what is the pressure of the mixture of gases?

Explanation:

Mass of O₂ gas = 43.1 g, molar mass of O₂ gas = 32.0 g/mol

Number of moles of O₂ gas = 43.1/32.0 = 1.347 moles

Mass of CO₂ gas = 6.8 g, molar mass of CO₂ gas = 44.0 g

Number of moles of CO₂ gas = 6.8/44 = 0.155 moles

Total number of moles of gas mixture, n = (1.347 + 0.155) = 1.502 moles

Volume of gas mixture, V = 13.7 L

Temperature of gas mixture, T = 34 °C = (273.15 + 34) K = 307.15 K

Pressure of gas mixture = ?

Molar gas constant, R = 0.0821 liter·atm/mol·K.

Using the ideal gas equation: PV =nRT

P = nRT/V

P = (1.502 × 0.0821 × 307.15) / 13.7

P = 2.76 atm

Therefore, the total pressure of the gas mixture = 2.76 atm

5 0

3 years ago

Does the antifreeze you put in a car radiator have a lower or higher freezing point than water

saveliy_v [14]

Hello!
Antifreeze says it in the name. This means that it helps prevent freezing. The liquid that would freeze if you wouldnt use the antifreeze is water. This means that the antifreeze has to have a higher freezing point then water, because otherwise it would only freeze faster!

Hope this helped you!

7 0

3 years ago

etermine the number of valence electrons for each of the atoms. Enter each answer as a numeral. For example, if an atom has two

Sav [38]

Answer:

1. 1

2. 2

3. 6

4. 8

Explanation:

Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others. Thus, this property is typically used to determine the chemical properties of elements.

1. Li is the symbol for the chemical element known as Lithium: it has 1 valence electron. The electronic configuration of lithium is 1s²2s¹

2. Mg is the symbol for the chemical element known as Magnesium: it has 2 valence electrons. The electronic configuration of magnesium is 1s²2s²2p63s²

3. O is the symbol for the chemical element known as Oxygen: it has 6 valence electrons. The electronic configuration of magnesium is 1s²2s²2p⁴.

4. Ne is the symbol for the chemical element known as Neon: it has 8 valence electrons.

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3 years ago

What is the difference between minerals and rocks?

Natasha2012 [34]

What's the difference between rocks and minerals?A mineral is a naturally occurring, inorganic solid with a definite chemical composition and a crystalline structure formed by a geological processes. A rock is an aggregate of one or more minerals where as a rock may also include organic remains and mineraloids.

I hope this helps

7 0

3 years ago

What’a the structure of 4-ethyl-2,2-dimethylheptane?

Slav-nsk [51]

PubChem CID: 142982

Chemical Names: 4-Ethyl-2,2-dimethylhexane; Hexane, 4-ethyl-2,2-dimethyl-; 52896-99-8; 2,2-dimethyl-4-ethylhexane; AC1L3M80; Hexane,4-ethyl-2,2-dimethyl- More...

Molecular Formula: C10H22

Molecular Weight: 142.286 g/mol

InChI Key: QHLDBFLIDFTHQI-UHFFFAOYSA-N

7 0

3 years ago