All categories

3 years ago

If an element has 12 protons, 13 neutrons, and 15 electrons, what is its mass?

Chemistry

1 answer:

-BARSIC- [3]3 years ago

7 0

Answer:

Explanation:

mass number = protons + neutrons

= 13 + 12 = 25

You might be interested in

When heated, solid copper(ii) carbonate decomposes to solid copper(ii) oxide and carbon dioxide gas. give the balanced chemical

RideAnS [48]

CuCO3(s) -----T---> CuO(s) + CO2(g)

:-) ;-)

8 0

3 years ago

Sulfur dioxide, SO 2 ( g ) , can react with oxygen to produce sulfur trioxide, SO 3 ( g ) , by the reaction 2 SO 2 ( g ) + O 2 (

aleksley [76]

<u>Answer:</u> The amount of heat produced by the reaction is -21.36 kJ

<u>Explanation:</u>

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles.

The equation used to calculate enthalpy change is of a reaction is:

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

For the given chemical reaction:

$2SO_2(g)+O_2(g)\rightarrow 2SO_3(g)$

The equation for the enthalpy change of the above reaction is:

$\Delta H_{rxn}=[(2\times \Delta H_f_{(SO_3(g))})]-[(2\times \Delta H_f_{(SO_2(g))})+(1\times \Delta H_f_{(O_2(g))})]$

We are given:

$\Delta H_f_{(SO_2(g))}=-296.8kJ/mol\\\Delta H_f_{(SO_3(g))}=-395.7kJ/mol\\\Delta H_f_{(O_2(g))}=0kJ/mol$

Putting values in above equation, we get:

$\Delta H_{rxn}=[(2\times (-395.7))]-[(2\times (-296.8))+(1\times (0))]\\\\\Delta H_{rxn}=-197.8kJ/mol$

To calculate the number of moles, we use ideal gas equation, which is:

$PV=nRT$

where,

P = pressure of the gas = 1.00 bar

V = Volume of the gas = 2.67 L

n = number of moles of gas = ?

R = Gas constant = $0.0831\text{ L. bar }mol^{-1}K^{-1}$

T = temperature of the mixture = $25^oC=[25+273]K=298K$

Putting values in above equation, we get:

$1.00bar\times 2.67L=n\times 0.0831\text{ L. bar }mol^{-1}K^{-1}\times 298K\\\\n=\frac{1\times 2.67}{0.0831\times 298}=0.108mol$

To calculate the heat released of the reaction, we use the equation:

$\Delta H_{rxn}=\frac{q}{n}$

where,

q = amount of heat released = ?

n = number of moles = 0.108 moles

$\Delta H_{rxn}$ = enthalpy change of the reaction = -197.8 kJ/mol

Putting values in above equation, we get:

$-197.8kJ/mol=\frac{q}{0.108mol}\\\\q=(-197.8kJ/mol\times 0.108mol)=-21.36kJ$

Hence, the amount of heat produced by the reaction is -21.36 kJ

3 0

3 years ago

ASAP please 50 points!!!

SSSSS [86.1K]

Which of the following is a change in physical composition?it could be D. A brick being ground up into fine dust. as this is a change from one physical form to another Which of the following is a change in chemical composition? would be A. A white precipitate forming as a result of the combination of two liquids. as this is a clear chemical change What kind of bond would you expect between H, S and O? i belive it would be D. Covalent

Which of the following is not one of the three processes of the hydrologic cycle? this gose to B. Collection the water cycle has nothing to do with this so there for its not part of the cycle

5 0

3 years ago

Give the half-equation for the reaction at the anode, during

oee [108]

The answer would be B

3 0

3 years ago

a cold glass of water is set outside on a hot day and water droplets develop on the outside of the glass describe whats happenin

notsponge [240]

It is basically condensation

4 0

3 years ago

Read 2 more answers