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3 years ago

Write the complete symbol, including mass number and atomic number, for each atom.

Chemistry

1 answer:

Reil [10]3 years ago

8 0

Answer:

a) 58Ni

b) 43Ti

c) 34P

d) 18O

e) 58Ni

f) 43Ti

g)34P

h) 18O

i) 54Cr

Explanation:

a) contains 28 protons and 30 neutrons:

An atom with 28 protons and 30 neutrons has an atomic number of 28 and a mass number of (30+28) = 58.

The atom with atomic number 28 is Ni.

b) contains 22 protons and 21 neutrons:

An atom containing 22 protons and 21 neutrons has an atomic number of 22 and an atomic mass of (22+21) = 43

The atom with atomic number 22 is Titanium (Ti).

This is the 43Ti isotope of titanium

c) contains 15 electrons and 19 neutrons

An atom with 15 electrons would have the same amount of , 15 protons (considering it to be neutral) and has 19 neutrons.

Thus, the atomic number of the atom would be 15 and the mass number would be (15+19) = 34

The atom with atomic number 15 is phosphorus (P).

This is the 34P isotope of phosphorus

d) an oxygen atom with 10 neutrons:

Oxygen has an atomic number of 8, thus there are 8 protons in an atom of oxygen.

The mass number of the oxygen atom with 10 neutrons would be (8+10) = 18

This is 18O - isotope.

e) contains 28 protons and 30 neutrons:

An atom with 28 protons and 30 neutrons has an atomic number of 28 and a mass number of (30+28) = 58.

The atom with atomic number 28 is Ni.

f) contains 22 protons and 21 neutrons:

An atom containing 22 protons and 21 neutrons has an atomic number of 22 and an atomic mass of (22+21) = 43

The atom with atomic number 22 is Titanium (Ti).

This is the 43Ti isotope of titanium

g) contains 15 electrons and 19 neutrons:

An atom with 15 electrons would have the same amount of , 15 protons (considering it to be neutral) and has 19 neutrons.

Thus, the atomic number of the atom would be 15 and the mass number would be (15+19) = 34

The atom with atomic number 15 is phosphorus (P).

This is the 34P isotope of phosphorus

h) an oxygen atom with 10 neutrons:

Oxygen has an atomic number of 8, thus there are 8 protons in an atom of oxygen.

The mass number of the oxygen atom with 10 neutrons would be (8+10) = 18

This is 18O - isotope.

i) The atomic number of Cr is 24

The mass number is given to be 54.

This is the 54Cr isotope and has 24 protons and 30 neutrons

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$\Delta H^o_{rxn}=\sum [n\times \Delta H_f_{(product)}]-\sum [n\times \Delta H_f_{(reactant)}]$

For the given chemical reaction:

$4CH_3NH_2(g)+2H_2O(l)\rightarrow 3CH_4(g)+CO_2(g)+4NH_3(g)$

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$\Delta H_{rxn}=[(3\times \Delta H_f_{(CH_4(g))})+(1\times \Delta H_f_{(CO_2(g))})+(4\times \Delta H_f_{(NH_3(g))})]-[(4\times \Delta H_f_{(CH_3NH_2(g))})+(2\times \Delta H_f_{(H_2O(l))})]$

We are given:

$\Delta H_f_{(H_2O(l))}=-285.8kJ/mol\\\Delta H_f_{(NH_3(g))}=-46.1kJ/mol\\\Delta H_f_{(CH_4(g))}=-74.8kJ/mol\\\Delta H_f_{(CO_2(g))}=-393.5kJ/mol\\\Delta H_f_{(CH_3NH_2(g))}=-22.97kJ/mol$

Putting values in above equation, we get:

$\Delta H_{rxn}=[(3\times (-74.8))+(1\times (-393.5))+(4\times (-46.1))]-[(4\times (-22.97))+(2\times (-285.8))]\\\\\Delta H_{rxn}=-138.82kJ$

Hence, the standard heat for the given reaction is -138.82 kJ

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