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I am Lyosha [343]
3 years ago
12

How many moles of calcium (Ca) atoms are there in 77.4 g of Ca?

Chemistry
2 answers:
Vinvika [58]3 years ago
8 0
Lar mass of Ca<span> = 40.08 </span>grams/mole 77.4 g Ca<span> * ( 1 </span>mole Ca<span>/ 40.08 ... n = m / M 1mol </span>Ca<span>weights 40 gmol-1 n = 77,4 / 40 = 1.93 </span>mol<span>.</span>
iren [92.7K]3 years ago
3 0

Answer: 1.94 moles

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 6.023\times 10^{23} of particles.

To calculate the moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}

Given mass = 77.4 g

Molar mass = 40 g/mol

Putting in the values:

\text{Number of moles}=\frac{77.4g}{40g/mol}=1.94

Thus 1.94 moles of calcium atoms are there in 77.4 g of Ca.

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Answer:

Make an observation.

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Form a hypothesis, or testable explanation.

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3 years ago
Based on location in the periodic table, which element has chemical properties that are most similar to iodine
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Based on location in the periodic table, fluorine (F) has chemical properties that are most similar to iodine.

In the periodic table, elements are classified in groups and periods. The elements in the same group are chemically similar and they have the same number of valence electrons. Elements in the same period have the same highest energy level.

Hence, when looking for an element that is most chemically similar to iodine, we have to consider the element that is in the same group with iodine.

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Learn more: brainly.com/question/11155928

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3 years ago
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3 years ago
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vazorg [7]

Answer:

<em>What can be added to an atom to cause a nonvalence electron in the atom to temporarily become a valence electron </em>is<u><em> energy</em></u><em>.</em>

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The normal state of the atoms, where all the electrons are occupying the lowest possible energy level, is called ground state.

The <em>valence electrons</em> are the electrons that occupy the outermost shell, this is the electrons in the highest main energy level (principal quantum number) of the atom.

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To solve this problem we can use following equation.

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2 years ago
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