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3 years ago

Campare and Conteast Physical and chemical properties.

Chemistry

1 answer:

I am Lyosha [343]3 years ago

3 0

Answer:

Physical properties are changes in color, weight, mass, density, volume, whether it is freezing, tarnishing, boiling, etc. while chemical properties are changes in the compound of the object such as whether an object is/isn't flammable, affected by acid, it dissolves, ferments, rots, ignites in water, etc.

Explanation:

Physical property examples: a piece of steel is cut in half, a sugar cube is ground up into a powder, ice melts into water, clouds form in the sky, you mow the lawn, the water turned purple when you dropped red and blue dye in it, leaves grow in the spring, ethyl alcohol boils at 79° C, you cut apples up

Chemical property examples: pancakes cook on the griddle, fireworks explode in th sky, Alka-Seltzer gives off carbon dioxide when added to water, roasting a marshmellow, milk sours when left on the counter, burning wood in a bonfire, salt dissolves in water, food is digested in the stomach

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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]

Answer: The amount of heat produced by the reaction is -21.36 kJ

Explanation:

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

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3 years ago

Rus_ich [418]

Answer:

Multiple organisms may be affected by the loss of a plant species.

Explanation:

Organisms that feed directly off the lost plant will be affected, and because of that, organisms that feed off those organisms will be affected. This could also affect other organisms like parasites. Other plant species may be affected from the loss of a competitive species. This could affect organisms that feed off that plant, and the organisms that feed off those organisms.

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2 years ago

How does a allergy develop? PLEASE HELP!

Nikolay [14]

Allergies arise when a foreign material such as pollen, bee venom or pet dander responds to your immune system or a food that in most people does not cause a reaction. Substances known as antibodies are formed by your immune system.