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2 years ago

Lab: Physical and Chemical Changes Assignment: Lab Report Active HELP

Chemistry

1 answer:

arlik [135]2 years ago

4 0

Answer:

Explanation:

Physical Change:

The changes that occur only due to change in shape or form but their chemical or internal composition remain unchanged.

These changes were reversible.

They have same chemical property.

These changes can be observed with naked eye.

Example :

Water converting to Ice

Water converting to gas

In this water molecule remain the same only they rearrange themselves that change its state of mater not composition

Chemical changes:

The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.

These changes are irreversible

These changes occur due to chemical reactions

These may not be observed with naked eye

Example:

Combustion of fuel or wood: that oil or wood convert into energy, CO₂ and ash in case of wood

Boiling of egg: that change the chemical composition of protein in the egg

The reaction of Hydrogen and oxygen:

H₂ (g) + O₂ (g) -------------------------------------> 2H₂O (l)

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Why don't solids change shape?

borishaifa [10]

Answer: B) the forces in the solid hold the atoms tightly in place

Explanation:This is because there is no room for the atoms to move around much and because they are very close together which makes the phase a solid.

6 0

3 years ago

Ethanol (CH3CH2OH), the intoxicant in alcoholic beverages, is also used to make other organic compounds. In concentrated sulfuri

Fed [463]

Answer:

a) 88.48%

b) 0.05625 mol

Explanation:

2CH₃CH₂OH(l) → CH₃CH₂OCH₂CH₃(l) + H₂O(g) Reaction 1

CH₃CH₂OH(l) → CH₂═CH₂(g) + H₂O(g) Reaction 2

a) CH₃CH₂OH = 46.0684 g/mol

CH₃CH₂OCH₂CH₃ = 74.12 g/mol

1 mol CH₃CH₂OH ______ 46.0684 g

x ______ 50.0 g

x = 1.085 mol CH₃CH₂OH

1 mol CH₃CH₂OCH₂CH₃ ______ 74.12 g g

y ______ 35.9 g

y = 0.48 mol CH₃CH₂OCH₂CH₃

100% yield _____ 0.5425 mol CH₃CH₂OCH₂CH₃

w _____ 0.48 mol CH₃CH₂OCH₂CH₃

w = 88.48%

b) Only 0.96 mol of ethanol reacted to form diethyl ether. This means that 0.125 mol of ethanol did not react. 45% of 0.125 mol reacted to form ethylene. Therefore, 0.05625 mol of ethanol reacted by the side reaction (reaction 2). Since 1 mol of ethanol leads to 1 mol of ethylene, 0.05625 mol of ethanol produces 0.05625 mol of ethylene.

4 0

3 years ago

Need help !!!!! ASAP

Ksivusya [100]

<h2>Hello!</h2>

The answer is:

We have that there were produced 0.120 moles of $CO_{2}$

$n=0.120mol$

We are asked to calculate the number of moles of the given gas, also, we are given the volume, the temperature and the pressure of the gas, we can calculate the approximate volume using The Ideal Gas Law.

The Ideal Gas Law is based on Boyle's Law, Gay-Lussac's Law, Charles's Law, and Avogadro's Law, and it's described by the following equation:

$PV=nRT$

Where,

P is the pressure of the gas.

V is the volume of the gas.

n is the number of moles of the gas.

T is the absolute temperature of the gas (Kelvin).

R is the ideal gas constant (to work with pressure in mmHg), which is equal to:

$R=62.363\frac{mmHg.L}{mol.K}$

We must remember that the The Ideal Gas Law equation works with absolute temperatures (K), so, if we are given relative temperatures such as Celsius degrees or Fahrenheit degrees, we need to convert it to Kelvin before we proceed to work with the equation.

We can convert from Celsius degrees to Kelvin using the following formula:

$Temperature(K)=Temperature(C\°) + 273K$

So, we are given the following information:

$Pressure=760mmHg\\Volume=2.965L\\Temperature=25.5C\°=25.5+273K=298.5K$

Now, isolating the number of moles, and substituting the given information, we have:

$PV=nRT$

$n=\frac{PV}{RT}$

$n=\frac{760mmHg*2.965L}{62.363\frac{mmHg.L}{mol.K}*298.5K}$

$n=\frac{760mmHg*2.965L}{62.363\frac{mmHg.L}{mol.K}*298.5K}\\\\n=\frac{2242mmHg.L}{18615.355\frac{mmHg.L}{mol.}}\\\\n=0.120mole$

Hence, we have that there were produced 0.120 moles of $CO_{2}$

$n=0.120mol$

Have a nice day!

7 0

3 years ago

In the Haber reaction, patented by German chemist Fritz Haber in 1908, dinitrogen gas combines with dihydrogen gas to produce ga

Reptile [31]

Answer:

The rate at which ammonia is being produced is 0.41 kg/sec.

Explanation:

$N_2+3H_2\rightarrow 2NH_3$ Haber reaction

Volume of dinitrogen consumed in a second = 505 L

Temperature at which reaction is carried out,T= 172°C = 445.15 K

Pressure at which reaction is carried out, P = 0.88 atm

Let the moles of dinitrogen be n.

Using an Ideal gas equation:

$PV=nRT$

$n=\frac{PV}{RT}=\frac{0.88 atm\times 505 L}{0.0821 atm l/mol K\times 445.15 K}=12.1597 mol$

According to reaction , 1 mol of ditnitrogen gas produces 2 moles of ammonia.

Then 12.1597 mol of dinitrogen will produce :

$\frac{2}{1}\times 12.1597 mol=24.3194 mol$ of ammonia

Mass of 24.3194 moles of ammonia =24.3194 mol × 17 g/mol

=413.43 g=0.41343 kg ≈ 0.41 kg

505 L of dinitrogen are consumed in 1 second to produce 0.41 kg of ammonia in 1 second. So the rate at which ammonia is being produced is 0.41 kg/sec.

6 0

3 years ago

Explain how the study of taxonomy helps other scientists.

katrin [286]

The classification of living things makes it easier for scientists to answer many important questions.
Examples:
-How many known species are there?
-What are the defining characteristics of each species?
-What are the relationships between these species?

4 0

3 years ago