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3 years ago

Explain how chemical change differs from a physical change

2 answers:

8 0

A chemical change affects on the molecular level of matter, which makes it irreversible. Combustion is a pretty good exmple. Physical changes are reversible and dont alter the formula. Hope this helped!

VashaNatasha [74]3 years ago

3 0

<span>A physical change is also generally reversible, while a chemical change is not. :)

</span>

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Bauxite must go through two processes to produce aluminum metal. The yield of the Bayer process, which extracts aluminum oxide f

Mashcka [7]

The yield of aluminium obtained from 1 m^3 of bauxite is 419810 g

<h3>What is a Percent yield</h3>

A percent yield of a substance measures the amount of the substance actually obtained as a percentage ratio of expected yield.

Percent yield = actual yield / expected yield × 100%

<h3>How to calculate the mass of aluminium obtained from bauxite </h3>

From the data given:

40 % of the bauxite is converted to aluminium oxide.

Volume of bauxite = 1 m^3

40 % of 1 m^3 = 0.4 m^3

volume of aluminium oxide = 0.4 m^3

density of aluminium oxide = 3965 kg/m^3

Using mass = density × volume

mass of aluminium oxide = 0.4 × 3965 kg

mass of aluminium oxide = 1586 kg

Formula of aluminium oxide is Al203

molar mass of aluminium oxide = 102 g

percentage mass of aluminium in one mole of aluminium oxide = mass of aluminium / mass of aluminium oxide × 100 %

Percentage mass of aluminium in aluminium oxide = 54/102 × 100

Percentage mass of aluminium in aluminium oxide = 52.94 %

Expected mass of aluminium from aluminium oxide = 52.94 × 1586

Expected mass of aluminium = 839.62 kg

Actual yield = 40 % × 839.62

Actual yield of aluminium = 419.81 kg

mass of aluminium in grams = 419810 g

Therefore, mass of aluminium obtained from 1 m^3 of bauxite is 419810 g

Learn more about percent yield at: brainly.com/question/8638404

3 0

2 years ago

Solid potassium hydroxide koh decomposes into gaseous water and solid potassium oxide . write a balanced chemical equation for t

galina1969 [7]

<span>The chemical formula is pretty straightforward. 2KOH reacts to produce H2O and K2O. This is the balanced chemical reaction between: Solid potassium hydroxide koh decomposing into gaseous water and solid potassium.</span>

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3 years ago

A sample of salt (sodium chloride) is placed on the tip of a platinum wire. When the sample is heated on blue flame the flame tu

gulaghasi [49]

So platinum is a transition metal. In general transition metals are reducers, which means they can give the electrons they have, to the sodium atoms. Also in chemistry we look at sub orbitals rather that shells(2,8,8). So due to the energy from heat, the d orbital split as electrons move to a higher energy level. Some of the electrons are given to the sodium ions and therefore the flame changes colour to yellow.
The excitation of the electrons is caused by them getting energy and so moving up an energy level. This energy is released and the electron returns to it's original state. The energy released, however, does not release in the same direction, but in different/various directions. Therefore the colour of the light changes as some energy is released in the surrounding.

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3 years ago

Be sure to answer all parts.The combustion of a 40.0−g gaseous mixture of H2 and CH4 releases 3766 kJ of heat. Calculate the amo

Svetach [21]

Answer:H2=11.4g

CH4=28.6g

Explanation:The complete combustion of the two gases can be represented by a balanced reaction below

1. CH4 +2O2___CO2+2H2O

2.2H2+O2___2H2O

Combining the two we have CH4 +2H2+3O2___

CO2+4H2O

Since the mixture contains 40gof CH4 and 2, therefore 20g of CH4 and 8g of H2 combines.

Calculated from their molecular Mass i.e CH4 12+4×2)=20 and 2H2= 2×2×2=8g

Mass of CH4=20/28×40=28.6g

2H2=8/28×40=11.4g

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3 years ago

An alpha particle is equivalent to a _____ nucleus.

Allushta [10]

An alp-ha particle is equivalent to the nucleus of a helium atom. Helium Atom = Answer.

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3 years ago

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