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kirill [66]
3 years ago
5

Which of the following is a pure substance?

Chemistry
1 answer:
makvit [3.9K]3 years ago
8 0
<span>A pure substance is defined as a matter having definite and constant composition all throughout a sample. It is held by chemical bonds therefore only chemical processes can be used to break it. I think the correct answer among the choices listed is option D.</span>

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6. 100 ml of gaseous hydrocarbon consumes 300
mario62 [17]

Answer:

  • <u><em>a. C₂H₄</em></u>

Explanation:

At constant pressure and temperature, the mole ratio of the gases is equal to their volume ratio (a consequence of Avogadro's law).

Hence, the <em>complete combustion reaction</em> that has a ratio of 100 ml of gaseous hydrocarbon to 300 ml of oxygen, is that whose mole ratio is 1 mol hydrocarbon : 3 mol of oxygen.

Then, you must write the balanced chemical equations for the complete combustion of the four hydrocarbons in the list of choices, and conclude which has such mole ratio (1 mol hydrocarbon : 3 mol oxygen).

A complete combustion reaction of a hydrocarbon is the reaction with oxygen that produces CO₂ and H₂O, along with the release of heat and light.

<u>a. C₂H₄:</u>

  • C₂H₄ (g) + 3O₂ (g) → 2CO₂(g)  + 2H₂O (g)

Precisely, for this reaction the mole ratio is 1 mol C₂H₄: 2 mol O₂, hence, this is the right choice.

The following analysis just shows that the other options are not right.

<u>b. C₂H₂:</u>

  • 2C₂H₂ (g) + 5O₂ (g) → 4CO₂(g)  + 2H₂O (g)

The mole ratio for this reaction is 2 mol C₂H₂ :5 mol O₂.

<u>с. С₃Н₈</u>

  • C₃H₈ (g) + 5O₂ (g) → 3CO₂(g)  + 4H₂O (g)

The mole ratio is 1 mol C₃H₈ : 5 mol O₂

<u>d. C₂H₆</u>

  • 2C₂H₆ (g) +7 O₂ (g) → 4CO₂(g)  + 6H₂O (g)

The mole ratio is 2 mol C₂H₆ : 7 mol O₂

7 0
3 years ago
What is the frequency of the sinusoidal graph?
Arisa [49]

Answer:

For finding frequency, we need to first find the period of the graph.

The period of a sinusoidal graph is the time interval in which it repeats its pattern.

In the graph, we can see, after 1/period time, it repeats its pattern.

Hence the period of the graph is  \pi /2.

Now we need to find its frequency 1/\pi /2

The formula for frequency is 2/\pi

This is the answer

i hope you pass the assignment

try your best!

8 0
3 years ago
A student needs to convert a volume of 3 Tbsp (tablespoons) to mL. The student finds out that 1 tablespoon is equivalent to 14.7
garri49 [273]

Answer:

The conversion factor is 14.79 mL/Tbsp.

Explanation:

To do an unity conversiton, we can make a factor by a ratio transformation:

3 Tbsp * \frac{14.79 mL}{1Tbsp}

So, the conversion factor is 14.79 mL/Tbsp and 3 Tbsp has 44.37 mL.

3 0
3 years ago
What are some examples of chemistry research when it comes to energy
Airida [17]

Answer:

Here's what I've found

Explanation:

Refer to the attachment !

5 0
3 years ago
Question 14 A student dissolves 1.5g of styrene C8H8 in 225.mL of a solvent with a density of 1.02/gmL . The student notices tha
Yuki888 [10]

We must to know:

Cm = molarity = niu / Vs, when the niu = no. of moles and Vs = Volume of solution

the no. niu = mass / molecular mass of substance

molecular mass of C8H8 = 12x8+8x1 = 104 g/mol

=> niu = 1,5 / 104 = 0,0144 moles C8H8

=> Cm = 0,0144/0,225 = 0,06 mol/L

Cmm = molality = niu (C8H8) / mass of solvent (kg)

=> p = mass / V => mass (solvent) = p x V

=> 225 x 1,02 = 229,5 g solvent = 0,2295 kg solvent

=> Cmm = 0,0144 / 0,229,5 = 0,063

8 0
3 years ago
Read 2 more answers
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