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3 years ago

104. Fill in the blanks to complete the table.

Chemistry

1 answer:

iren2701 [21]3 years ago

3 0

Explanation:

Just a few things to remember:

# of neutrons = Mass number - # protons
Mass number = # protons + # neutrons
Atomic Number = # of protons
# of electrons = # of protons - charge on the atom
Symbol - use the atomic number to find the element in the periodic table

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Balance the following skeleton reaction and identify the oxidizing and reducing agents: Include the states of all reactants and

rusak2 [61]

Answer:

$4Zn_(_s_)~+~7OH^-~_(_a_q_)~+~NO_3^-_(_a_q_)~+~6H_2O_(_l_)~-->4Zn(OH)_4^-^2_(_a_q_)~+~NH_3_(_g_)$

-) Oxidizing agent: $NO_3^-_(_a_q_)$

-) Reducing agent: $Zn_(_s_)$

Explanation:

The first step is separate the reaction into the semireactions:

A. $Zn~->Zn(OH)_4^-^2$

B. $NO_3^-~->~NH_3$

If we want to balance in basic medium we have to follow the rules:

1. We adjust the oxygen with $OH^-$

2. We adjust the H with $H_2O$

3. We adjust the charge with $e^-$

Lets balance the first semireaction A. :

$Zn~+~4OH^-~->Zn(OH)_4^-^2~+~2e^-$

Now, lets balance semireaction B:

$NO_3^-~+~8e^-~+~6H_2O~->~NH_3~+~9OH^-$

Finally, we have to add the two semireactions:

_________________________________________

$8~(Zn~+~4OH^-~->Zn(OH)_4^-^2~+~2e^-)$

$2~(NO_3^-~+~8e^-~+~6H_2O~->~NH_3~+~9OH^-)$

_________________________________________

$(8Zn~+~32OH^-~->8Zn(OH)_4^-^2~+~16e^-)$

$(2NO_3^-~+~16e^-~+~12H_2O~->~2NH_3~+~18OH^-)$

Cancel out the species on both sides:

$8Zn~+~14OH^-~+~2NO_3^-~+~12H_2O~-->8Zn(OH)_4^-^2~+~2NH_3$

Simplifying the equation :

$4Zn~+~7OH^-~+~NO_3^-~+~6H_2O~-->4Zn(OH)_4^-^2~+~NH_3$

The $Zn_(_s_)$ is oxidized therefefore is the reducing agent. The $NO_3^-_(_a_q_)$ is reduced therefore is the oxidizing agent.

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4 years ago

What power source uses the earth’s internal heat?

neonofarm [45]

The answer is geothermal.
Geo (earth) and thermal (heat).

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3 years ago

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A neutral atom of Cl-37 has

Ostrovityanka [42]

Answer:

17 protons, 20 neutrons, and 17 electrons.

Explanation:

A periodic table can be defined as the standard arrangement of chemical elements by atomic number, electronic configuration and chemical properties in a tabular form.

Generally, a proper representation of the mass number and atomic number of chemical elements is key and very important in chemistry.

Furthermore, as a rule, it should be noted that the mass number (nucleon number) is always larger than the atomic number(number of proton).

The mass number of this neutral atom of Cl-37 is 37 and we know that the atomic number (number of protons) of chlorine is 17. Also, the atomic number of an element is equal to the number of its electrons.

A neutral atom of Cl-37 has 17 protons, 20 neutrons, and 17 electrons.

Hence, a neutral atom of Cl-37 can be identified based on its number of protons because it represent its atomic number, which is what is used to differentiate an atom of an element from the atom of another chemical element.

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3 years ago

What is the enthalpy change (in kJ) of a chemical reaction that raises the temperature of 250.0 ml of solution having a density

stellarik [79]

Answer:

328.4KJ

Explanation:

Before we move on to calculate enthalpy change, we calculate the amount of heat Q

Q= mcΔT

m = density * volume = 250 * 1.25 = 312.5g

c = 3.74J/g.k

ΔT = 7.80 + 273.15K = 280.95K

Q= 312.5 * 3.74 * 280.95 = 328,360.312 J= 328.4KJ(1000J = 1KJ, so divide by 1000)

The enthalpy change in the reaction is same as amount of heat transferred = 328.4KJ

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4 years ago

Does the lewis structure depict a neutral molecule or an ion? does the lewis structure depict a neutral molecule or an ion? the

Lina20 [59]

is this supposed to sound like an actual question? it looks like something computer generated to me, but, yes?

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