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san4es73 [151]
3 years ago
14

Pb has an atomic number of 82. It has an isotope Pb-207. The mass number is 207.

Chemistry
1 answer:
nikdorinn [45]3 years ago
5 0

Answer:

Number of protons = 82

Explanation:

Given data:

Atomic number of Pb = 82

Mass number of Pb-207 = 207

Number of protons = ?

Solution:

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

Atomic number of Pb = number of protons or electrons

82 = number of protons or electrons

Mass number = Number of protons + number of neutron

207 = 82 + number of neutron

Number of neutrons = 207 - 82

Number of neutrons = 125

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Answer is: 230 g.
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n - amount of substance.
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3 years ago
Whats the main difference between a double replacement reaction and a single replacement
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What was the oxygen crisis
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Please show some work For the reaction: NO(g) + 1/2 O2(g) → NO2(g) ΔH°rxn is -114.14 kJ/mol. Calculate ΔH°f of gaseous nitrogen
uranmaximum [27]

Answer:

148.04 kJ/mol

Explanation:

Let's consider the following thermochemical equation.

NO(g) + 1/2 O₂(g) → NO₂(g)      ΔH°rxn = -114.14 kJ/mol

We can find the standard enthalpy of formation (ΔH°f) of NO(g) using the following expression.

ΔH°rxn = 1 mol × ΔH°f(NO₂(g)) - 1 mol × ΔH°f(NO(g)) - 1/2 mol × ΔH°f(O₂(g))

ΔH°f(NO(g)) = 1 mol × ΔH°f(NO₂(g)) - ΔH°rxn - 1/2 mol × ΔH°f(O₂(g)) / 1 mol

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8 0
3 years ago
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qwelly [4]

Answer:

The 1st and 4th options are correct

I.the oxidized form has a higher affinity for electrons

IV. the greater the tendency for the oxidized form to accept electrons

Explanation:

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