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3 years ago

Please fill out completely for my understanding. Thank-You!

Chemistry

1 answer:

Archy [21]3 years ago

8 0

The atomic number,atomic mass,valence electrons and the formula for calculating the number of neutrons is also given.The following table has been completed below in the attachment.

Explanation:

Atomic Number:the number of protons /electrons present in the nucleus of an atom is called the atomic number.

Mass Number/Atomic Mass:the number of protons and neutrons present in a nucleus

Example: $C_{6} ^{12}$ ;here;6 implies the atomic number and 12 implies the mass number/atomic mass

No.of neutrons=Mass number-Number of protons

Valence electrons:the number of electrons present in the outer most shell of an atom are called valence electrons

Example:If we consider a carbon atom;as its electronic configuration is2,4 and it belongs to 4th group.Therefore the number of valency electrons in carbon is 4.

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Hunting lions has been banned in some parts of Africa. If this law is enforced, what can we expect to happen to the populations

k0ka [10]

The population would decrease, the more predators there are the more food needed for the species .

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3 years ago

Read 2 more answers

How many moles of aluminum metal are required to produce 4.04 L of hydrogen gas at 1.11 atm and 27 °C by reaction with HCl?

Strike441 [17]

Answer:

0.121 moles of aluminum metal are required to produce 4.04 L of hydrogen gas at 1.11 atm and 27 °C by reaction with HCl

Explanation:

This is the reaction:

2 Al(s) + 6 HCl(aq) → 2 AlCl₃ (aq) + 3 H₂(g)

To make 3 moles of H₂, we need 2 moles of Al.

By conditions given, we will find out how many moles of H₂ do we have.

Let's use the Ideal Gas Law

P. V = n . R . T

1.11 atm . 4.04L = n . 0.082 L.atm/mol.K . 300K

(1.11 atm . 4.04L) / (0.082 mol.K/L.atm . 300K) = n

0.182 mol = n

So the rule of three will be:

If 3 moles of H₂ came from 2 moles of Al

0.182 moles of H₂ will come from x

(0.182 .2) / 3 = 0.121 moles

4 0

3 years ago

iron is made by a reduction of iron oxide with carbon monoxide. Fe2O3+3CO-2Fe+3CO2. Calculate the mass of iron that can be forme

lyudmila [28]

Answer:

Mass = 88.12 g

Explanation:

Given data:

Mass of iron oxide = 126 g

Mass of iron formed = ?

Solution:

Chemical equation:

Fe₂O₃ + 3CO → 2Fe + 3CO₂

Number of moles of iron oxide:

Number of moles = mass/molar mass

Number of moles = 126 g/ 159.69 g/mol

Number of moles = 0.789 mol

Now we will compare the moles of iron with iron oxide.

Fe₂O₃ : Fe

1 : 2

0.789 : 2/1×0.789 = 1.578 mol

Mass of iron:

Mass = number of moles ×molar mass

Mass = 1.578 mol × 55.84 g/mol

Mass = 88.12 g

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3 years ago

What fundamental building block makes up all matter in the universe

Sloan [31]

The building block that makes up all matter in the universe is atoms.

Hope that helps you:)

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3 years ago

If the change of enthalpy of this reaction when proceeding left to right is +14 kcal, which chemical equation is correct?

bagirrra123 [75]

Answer:

N₂O₄ + 14 kcal ⇄ 2NO₂.

Explanation:

Since the sign of ΔH determines either the reaction is exothermic or endothermic:

+ve, the reaction is endothermic.

-ve, the reaction is exothermic.

∵ The change of enthalpy of this reaction when proceeding left to right is + 14 kcal (+ ve sign).

∴ The reaction is endothermic, the heat is a part of the reacatnts in the reaction.

So, the reaction is:

N₂O₄ + 14 kcal ⇄ 2NO₂.

7 0

3 years ago