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3 years ago

Explain how mixture melting points can be used to distinguish between two compounds

Chemistry

1 answer:

Over [174]3 years ago

5 0

generally melting point of mixture is always different from melting point of pure compound

lets say you have a two compounds called A and B

and you have a unknown compound called X which can be either A or B

now your target is to find unknown is really A or B right?

take some amount of X and mix it with A and B separately

out of these two mixtures one will be pure compound (because we initially assume that unknown can be either A or B)

suppose X + A is same melting with A then X is A

X +B will be less than the melting point of A or

suppose X+B is same melting point like B then X is B

X+A will be less than melting point of B

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Choose all of the options that demonstrate how humans are impacting the water cycle.

Fantom [35]

Answer:

A.) Air pollutants wash onto land and water bodies from precipitation

C.) Storm water runoff carries pollution

I hope I helped! ^-^

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2 years ago

How is 0.00036 written in scientific notation?

natta225 [31]

3.6 x 10^-4
I am writing this sentence because the answer does not reach the 20 character limit. Thank you have nice day! :D Cx :P

4 0

3 years ago

Helpppppppp plzzzzzz asaaaapppp

9966 [12]

Answer:

Alright, the first thing we have to do is to balance the chemical equation

2Na3N -----> 6Na + 1N2

We have 60g of Na3N, we convert them into moles by dividing the mass of the compound by the molar mass.

Molar mass of Na3N = (22.98 x 3) + (14) = 82.94g/mol

60 = 0.72341451651 moles of Na3N

82.94

Now because we did the balanced equation, we know the mole to mole ratio of Na3N to N2 would be 2:1, so in order to get the moles of N2 you have to divide the moles of Na3N by 2

0.72341451651 moles/2 = 0.361707258 moles of N2

Now that we have the moles of N2, we just have to determine the mass of it in grams. In order to do that, just multiply the moles by the molar mass of N2 (28g/mol)

0.361707258 x 28 = 10.13g of N2

Therefore the decomposition of 60g of Na3N would result in 10.13g of N2 (nitrogen gas)

3 0

3 years ago

A. The half-life for a first order reaction in 49 minutes. What is the rate constant?B.For a second order reaction, the half-lif

Burka [1]

Answer:

a) 0,014 min⁻¹

b) 1452 seconds.

c) 0,02156 M

d) The faster rate is for the reaction A. The largest rate constant, k, is for A reaction

Explanation:

a) For a first order reaction the half-life is:

$t_{1/2} = \frac{ln(2)}{k}$ (1) As half.life is 49 min. Rate constant -k- is: 0,014 min⁻¹

b) The half-life is defined as the time that takes in descompose the half of the initial concentration of a compound.

As half-life is 726s. In 726s the concentration will be 0,300M, In the next 726s the concentration will be 0,150M. Thus, thae time it takes to decrease concentration until 0,150M is 726s×2= 1452 seconds

c) In the same way, 11072 years are 4 half-life for this reaction, thus:

0,345M/2⁴ = 0,02156 M

d) By definition of half-life, the less half-life, the faster rate. Thus, The faster rate is for the reaction A.

By (1) half-life is inversely proportional to rate constant. Thus, the less half-life, the largest rate constant. The largest rate constant, k, is for A reaction

I hope it helps!

7 0

3 years ago

What type of plate boundary is shown in the diagram below?

ryzh [129]

Answer : The second one

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3 years ago