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3 years ago

What is the number of protons plus the number of neutrons equal to?

Chemistry

1 answer:

Sedaia [141]3 years ago

3 0

Answer:

atomic number

Explanation:

The mass number of the atom (M) is equal to the sum of the number of protons and neutrons

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A 3.93 g sample of a laboratory solution contains 1.25 g of acid. what is the concentration of the solution as a mass percentage

WITCHER [35]

Divide 1.25/3.93 and then multiply by 100 to get the percent. This equals 31.81%

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3 years ago

What is the pH of a 3.9•10-8 M OH- solution

Mice21 [21]

POH will be -log[conc of OH]
-log (3.9E-08) = 7.409
pH = 14- pOH
pH = 14 - 7.409
pH = 6.59

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3 years ago

20 POINTS Given the number of protons, neutrons and electrons, find the mass and name of an isotope.

Dimas [21]

Answer:

Lithium

Pro.=3

Neu. =4

Elec.= 3

Mass = 6.941

Explanation:

3 0

3 years ago

or a particular isomer of C 8 H 18 , the combustion reaction produces 5104.1 kJ of heat per mole of C 8 H 18 ( g ) consumed, und

beks73 [17]

Answer:

The standard enthalpy of formation of this isomer of $C_{8}H_{18}$ is -220.1 kJ/mol.

Explanation:

The given chemical reaction is as follows.

$C_{8}H_{18}(g)+ \frac{25}{2}O_{2}(g) \rightarrow 8CO_{2}(g)+9H_{2}O(g)$

$\Delta H^{o}_{rxn}= -5104.1kJ/mol$

The expression for the entropy change for the reaction is as follows.

$\Delta H^{o}_{rxn}=[8\Delta H^{o}_{f}(CO_{2}) +9\Delta H^{o}_{f}(H_{2}O)]-[\Delta H^{o}_{f}(C_{8}H_{18})+ \frac{25}{2}\Delta H^{o}_{f}(O_{2})]$

$\Delta H^{o}_{f}(H_{2}O)= -241.8kJ/mol$

$\Delta H^{o}_{f}(CO_{2})= -393.5kJ/mol$

$\Delta H^{o}_{f}(O_{2})= 0kJ/mol$

Substitute the all values in the entropy change expression.

$-5104.1kJ/mol=[8(-393.5)+9(-241.8)kJ/mol]-[\Delta H^{o}_{f}(C_{8}H_{18})+ \frac{25}{2}(0)kJ/mol]$

$-5104.1kJ/mol=-5324.2kJ/mol -\Delta H^{o}_{f}(C_{8}H_{18})$

$\Delta H^{o}_{f}(C_{8}H_{18}) =-5324.2kJ/mol +5104.1kJ/mol$

$=-220.1kJ/mol$

Therefore, The standard enthalpy of formation of this isomer of $C_{8}H_{18}$ is -220.1 kJ/mol.

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3 years ago

How are metal atoms arranged according to metallic bonding ?

Paladinen [302]

Metallic bonding
Metals consist of giant structures of atoms arranged in a regular pattern. The electrons from the outer shells of the metal atoms are delocalised , and are free to move through the whole structure. This sharing of delocalised electrons results in strong metallic bonding .

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2 years ago