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3 years ago

Compare and contrast chemical change and physical change

1 answer:

3 0

Well physical would be if you have Clay and you molded into a new shape or if you put butter on your toes and it melts or water evaporating from the surface of the ocean chemical changes would be milk going sour jewellery tarnishing which means turning into a different color or rust bread putting it in the oven and turning it into toes or rust forming on the nail that is left outside

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Energy is the ability to do work or produce heat. True False

Dmitrij [34]

Answer: true

Explanation: hope this helpes

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3 years ago

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Calculate the number of grams of carbon dioxide produced from 6 moles of oxygen gas. List only the number of grams of carbon dio

faust18 [17]

Answer:

g CO2(g) = 264.06 g

Explanation:

C(s) + O2(g) → CO2(g)

∴ moles O2(g) = 6 mol

∴ mm CO2 = 44.01 g/mol

⇒ mol CO2(g) = ( 6 mol O2(g) )×( mol CO2(g) / mol O2(g) ) = 6 mol CO2(g)

⇒ mass CO2(g) = ( 6 mol CO2(g) )×( 44.01 g/mol ) = 264.06 g CO2(g)

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3 years ago

The rate of disappearance of hbr in the gas phase reaction 2hbr(g)?h2(g)+br2(g) is 0.160 m s-1 at 150°c. the rate of appearance

luda_lava [24]

The reaction rates of the substances whether disappearance of a reactant or the appearance of a product are related to each other by the chemical reaction. The reaction rates are related as follows:

rate = rHBr / 2 = rBr2 = rH2

rH2 = 0.160 / 2 = 0.08 M/s

8 0

3 years ago

If an electron travels at a velocity of 1.000 x 107 m/s and has a mass of 9.109 x 10-28 g, what is its wavelength?

alina1380 [7]

Good luck i don’t even know

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2 years ago

Ethanol (C2H5OH) melts a - 144 oC and boils at 78 °C. The enthalpy of fusion of ethanol is 5.02 kj/mol, and its enthalpy of vapo

hammer [34]

Answer:

For a: The total heat required is 36621.5 J

For b: The total heat required is 58944.5 J

Explanation:

For a:

To calculate the heat required at different temperature, we use the equation:

$q=mc\Delta T$ .........(1)

where,

q = heat absorbed

m = mass of substance

$c$ = specific heat capacity of substance

$\Delta T$ = change in temperature

To calculate the amount of heat required at same temperature, we use the equation:

$q=m\times \Delta H$ ........(2)

where,

q = heat absorbed

m = mass of substance

$\Delta H$ = enthalpy of the reaction

The processes involved in the given problem are:

$1.)C_2H_5OH(l)(35^oC)\rightarrow C_2H_5OH(l)(78^oC)\\2.)C_2H_5OH(l)(78^oC)\rightarrow C_2H_5OH(g)(78^oC)$

For process 1:

We are given:

Change in temperature remains the same.

$m=42.0g\\c_l=2.3J/g.K\\T_2=78^oC\\T_1=35^oC\\\Delta T=[T_2-T_1]=[78-35]^oC=43^oC=43K$

Putting values in equation 1, we get:

$q_1=42.0g\times 2.3J/g.K\times 43K\\\\q_1=4153.8J$

For process 2:

We are given:

Conversion factor: 1 kJ = 1000 J

Molar mass of ethanol = 46 g/mol

$m=42.0g\\\Delta H_{vap}=38.56kJ/mol=\frac{35.56kJ}{1mol}\times (\frac{1000J}{1kJ})\times (\frac{1}{46g/mol})=773.04J/g$

Putting values in equation 2, we get:

$q_2=42.0g\times 773.04J/g\\\\q_2=32467.7J$

Total heat required = $[q_1+q_2]$

Total heat required = $[4153.8J+32467.7J]=36621.5J$

Hence, the total heat required is 36621.5 J

For b:

The processes involved in the given problem are:

$1.)C_2H_5OH(s)(-155^oC)\rightarrow C_2H_5OH(s)(-144^oC)\\2.)C_2H_5OH(s)(-144^oC)\rightarrow C_2H_5OH(l)(-144^oC)\\3.)C_2H_5OH(l)(-144^oC)\rightarrow C_2H_5OH(l)(78^oC)\\4.)C_2H_5OH(l)(78^oC)\rightarrow C_2H_5OH(g)(78^oC)$