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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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What mass of xenon tetrafluoride, xef 4 , has the same number of fluorine atoms as 25.0 g of oxygen difluoride, of2?

nasty-shy [4]

To determine the mass of xenon tetrafluoride, we need to know first the number of fluorine atoms present in <span>oxygen difluoride. We need to convert first the mass into moles then make use of the relation of the elements from the chemical formula. Then, use the avogadro's number to convert it to number of atoms. Then, we do the reverse of the steps above but this time for </span><span>xenon tetrafluoride.

25.0 g OF2 ( 1 mol / 54 g ) ( 2 mol F / 1 mol OF2 ) ( 6.022 x10^23 atoms F / 1 mol F ) ( 1 mol / 6.022x10^23 atoms) ( 1 mol XeF4 / 4 mol F ) (207.3 g / 1 mol XeF4) = 47.99 g XeF4</span>

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3 years ago

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Nai(aq)+hg2(no3)2(aq)→ express your answer as a chemical equation. identify all of the phases in your answer. enter noreaction i

Komok [63]

<span>Balanced chemial equation:

2NaI(aq)+Hg2(NO3)2(aq) →Hg2 I2 (s) + 2 NaNO3 (aq)

You can see it better if I use latex:

$2NaI(aq)+Hg_2(NO_3)_2(aq) =Hg_2 I_2 (s) + 2 NaNO_3 (aq)$

As per the phases this is the interpretation:

The symbols (aq) stands for aquous meaning that the compound is dissolved in water.

The symbol (s) stands for solid, meaning tha the compound precipitate and is not dissolved in water.</span><span>

</span>

7 0

4 years ago

If you run this reaction with 15 g of CuCl2 and 20 g NaNO3, what is the theoretical yield of NaCl?

Margaret [11]

The theoretical yield of a substance is the amount of the mass that is calculated from stoichiometry. The mass of sodium chloride produced is 13.03 gms.

Mass of the substance is a multiplication of the molar mass and moles.

The balanced reaction is given as:

CuCl₂ + 2NaNO₃ ⇒ 2NaCl + Cu(NO₃)₂

Moles of copper chloride are calculated as: 15 ÷ 134.45 = 0.115 moles

Moles of sodium nitrate are calculated as: 20 ÷ 84.99 = 0.2353 moles

From the reaction, 1 mole of copper chloride gives 2 moles of sodium chloride so, 0.115 moles of copper chloride will produce 0.223 moles.

Similarly, 2 moles of sodium nitrate produce 2 moles of sodium chloride so, 0.2353 moles produce 0.4706 moles.

From this, it can be concluded that copper chloride is a limiting reagent and will be used to calculate the mass of NaCl.

Mass of NaCl is calculated as: Mass = 0.223 moles × 58.44 = 13.03 gms.

Therefore, 13.03 gms is the theoretical yield of sodium chloride.

Learn more about theoretical yield here:

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7 0

2 years ago

Atomic theory question Rutherford’s model

baherus [9]

Answer:

bounce

Explanation:

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3 years ago

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4 NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)

Mariulka [41]

Answer:

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Explanation:

Use mole ratios:

5 : 6

divide by 5 on both sides

1 : 1.2

multiply by 0.75 on both sides

0.75 : 0.9

So the result is 0.9 moles of water

(Please correct me if I'm wrong)

5 0

2 years ago