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4 years ago

He image shows the representation of an unknown element in the periodic table.

Chemistry

2 answers:

alexandr402 [8]4 years ago

8 0

Answer:

the number of neutrons in an atom of the element is 10.

Explanation:

neutron: mass # -protons

neutron: 19 (18.9984 (rounded)) - 9

neutron: 19- 9 =10

whole number is equal to the number of protons.

bekas [8.4K]4 years ago

3 0

Answer: Option (b) is the correct answer.

Explanation:

Atomic number is the sum of total number of protons present in an atom. And, atomic mass is the sum of total number of protons and neutrons present in an element.

Also, in a neutral atom the number of protons equal to the number of electrons.

Generally, atomic number is written on the top right corner of the symbol of an element and atomic mass is written at the bottom.

So here, number 9 is the atomic number and its atomic mass will be approximately 19.

Therefore, number of neutrons present in the given element will be as follows.

Atomic mass = no. of protons + no. of neutrons

19 = 9 + no. of neutrons

no. of neutrons = 19 - 9

= 10

Thus, we can conclude that the statement number of neutrons in an atom of the element is 10, is true.

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how many grams of calcium oxide will be produced in a closed vessel containing 20.0 kg of calcium and 20.0 kg of oxygen gas if t

sergejj [24]

Answer:

27984.1311 g

Explanation:

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

For calcium :-

Mass of calcium = 20.0 kg = 20000 g ( 1 kg = 1000 g )

Molar mass of calcium = 40.078 g/mol

Thus,

$Moles= \frac{20000\ g}{40.078\ g/mol}$

$Moles\ of\ calcium= 499.0269\ mol$

For oxygen gas :-

Mass of oxygen gas = 20.0 kg = 20000 g ( 1 kg = 1000 g )

Molar mass of oxygen gas = 31.999 g/mol

Thus,

$Moles= \frac{20000\ g}{31.999\ g/mol}$

$Moles\ of\ oxygen\ gas= 625.0195\ mol$

According to the given reaction:

$2Ca+O_2\rightarrow 2CaO$

2 moles of calcium reacts with 1 moles of oxygen gas

Also,

1 mole of calcium react with 1/2 mole of oxygen gas

So,

499.0269 mole of calcium react with $\frac{1}{2}\times 499.0269$ mole of oxygen gas

Moles of oxygen gas = 249.5135 moles

Available moles of oxygen gas = 625.0195 moles

Limiting reagent is the one which is present in small amount. Thus, calcium is limiting reagent.

The formation of the product is governed by the limiting reagent. So,

2 moles of calcium produces 2 moles of calcium oxide

So,

1 mole of calcium produces 1 mole of calcium oxide

Also,

499.0269 mole of calcium produces 499.0269 mole of calcium oxide

Moles of calcium oxide = 499.0269 moles

Molar mass of calcium oxide = 56.0774 g/mol

Mass of calcium oxide = Moles × Molar mass = 499.0269 × 56.0774 g = 27984.1311 g

27984.1311 g of calcium oxide will be produced.

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What is the pH level of soda?

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3 years ago

For the reaction 6CO2(g) + 6H2O(l) > C6H12O6(s) + 6O2(g), what mass, in grams, of glucose is produced from 3.00 moles of carb

aivan3 [116]

Answer:

Mass = 90.1 g

Explanation:

Given data:

Number of moles of carbon dioxide = 3 moles

Mass of glucose produced = ?

Solution:

Chemical equation:

6H₂O + 6CO₂ → C₆H₁₂O₆ + 6O₂

Now we will compare the moles of CO₂ and C₆H₁₂O₆.

CO₂ : C₆H₁₂O₆

6 : 1

3 : 0.5

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gogolik [260]

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Over [174]

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