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Goryan [66]
3 years ago
11

In a laboratory experiment, a fermenting aqueous solution of glucose and yeast produces carbon dioxide gas and ethanol. The solu

tion was heated by burning natural gas in a Bunsen burner to distill the ethanol that formed in the flask. During the distillation, the ethanol evaporated and then condensed in the receiving flask. The flame of the burner was kept too close to the bottom of the flask and some of the glucose decomposed into a black carbon deposit on the inside of the flask. During this experiment the following changes occurred. Which of these changes involved a physical change and not a chemical change?
1. evaporation of ethanol
2. condensation of ethanol
3. formation of a carbon deposit inside the flask
4. formation of carbon dioxide gas from glucose
5. burning of natural gas
6. formation of ethanol from glucose by yeast
Chemistry
1 answer:
Serggg [28]3 years ago
5 0

Answer:

1. evaporation of ethanol

2. condensation of ethanol

Explanation:

The first and second process imply a change of phase, which is essentially a  physical change because the matter change from liquid to gas and from gas to liquid respectively and it can ve reversed.

The options 3 to 6 are related to a chemical reaction because the outcomes of the process are different compounds than the ones we had at the beginning. The main reaction that implies process 3 to 6 is represented by:

C6H12O6 +  impurities → 2 C2H5OH + 2 CO+ C

For option 5. burning of natural gas , we have:

Natural gas(Mainly a mix of CH4 and C2H10) +O2→COn+H2O

Therefore, justo 1 and 2 are a physical change

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If 125 g of CaCO3 is mixed and reacted with 125 g of HCl, which reactant is limiting and how many grams of CO2 can be made?
Trava [24]

Answer:

CaCO3 is the limiting reactant

55 g of CO2 is made

Explanation:

First we must put down the reaction equation;

CaCO3(s) + 2HCl(aq) ---------> CaCl2(s) + H2O(l) + CO2(g)

Number of mole of CaCO3 = 125g/100gmol-1 = 1.25 moles

From the reaction equation;

1 mole of CaCO3 yields 1 mole of CO2

Hence 1.25 moles of CaCO3 yields 1.25 moles of CO2

For HCl;

number of moles of HCl = 125g/36.5 g mol-1 = 3.42 moles

From the reaction equation;

2 moles of HCl yields 1 mole of CO2

3.42 moles of HCl yields 3.42 * 1/2 = 1.71 moles of CO2

Hence CaCO3 is the limiting reactant.

Mass of CO2 produced = 1.25g * 44 gmol-1 = 55 g of CO2

6 0
2 years ago
What does the 32.06 represent?
lana [24]

The 32.06 represent The atomic mass, the average number of protons & neutrons

<h3>Further explanation </h3>

The Atomic Number (Z) indicates the number of protons in an atom of an element. If the atom is neutral then the number of protons will be equal to the number of electrons. So the atomic number can also indicate the number of electrons.

So atomic number = number of protons = number of electrons

Mass Number (A) is the sum of protons and neutrons

Mass Number (A) = Number of protons + Number of Neutrons

So that the relationship between atomic numbers and mass numbers can be formulated as follows:

Atomic Number (Z) = Mass Number (A) - Number of Neutrons

In the following element notation,

\large {{{Z} \atop {A}} \right X}

X = symbol of elemental atom

A = mass number

   = number of protons + number of neutrons

Z = atomic number

   = number of protons = number of electrons, on neutral elements

4 0
3 years ago
How many moles of water are formed when 22 mol of methane combusts?
icang [17]
Methane is a hydrocarbon which when burns in air (combustion) produces carbon dioxide and water. The equation for the reaction;
CH4 +2O2 = CO2 +2H2O
When one mole of methane combusts 2 moles of water are formed
Therefore; when 22 moles of methane combusts 44 moles of water are formed (22 ×2)
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3 years ago
Which is the smallest particle into which water (H2O) in a glass can be broken down and still remain water? A. a water molecule
Gnesinka [82]

Answer:-

A. A water molecule

Explanation:-

A molecule is the smallest particle of a compound that retains all it's chemical properties.

Here H2O is a compound. So the smallest particle that will retain all the chemical properties and still remain water is water molecule.

Atoms Hydrogen and Oxygen both have different chemical properties from water H2O and are thus different.

Hydrogen peroxide is different molecule from water. So it is also not water.

6 0
3 years ago
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All the elements of a family in the periodic table have what feature in common?
SCORPION-xisa [38]

They all have the same number of electrons in the electron cloud.

4 0
3 years ago
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