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3 years ago

Is caffeine additive?

Chemistry

2 answers:

Romashka-Z-Leto [24]3 years ago

7 0

Answer:

yes

Explanation:

yes

prohojiy [21]3 years ago

3 0

Yessesssssssssssssss

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Which explains why mixtures can be separated?

Elza [17]

Answer:

Explanation:

In chemistry, a mixture is a material made up of two or more different substances which are not chemically combined. A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions, and colloids.

5 0

3 years ago

Read 2 more answers

The activation energy of an uncatalyzed reaction is 70 kJ/mol. When a catalyst is added, the activation energy (at 20 °C) is 42

denis23 [38]

Answer:

T = 215.33 °C

Explanation:

The activation energy is given by the Arrhenius equation:

$k = Ae^{\frac{-Ea}{RT}}$

<u>Where:</u>

k: is the rate constant

A: is the frequency factor

Ea: is the activation energy

R: is the gas constant = 8.314 J/(K*mol)

T: is the temperature

We have for the uncatalyzed reaction:

Ea₁ = 70 kJ/mol

And for the catalyzed reaction:

Ea₂ = 42 kJ/mol

T₂ = 20 °C = 293 K

The frequency factor A is constant and the initial concentrations are the same.

Since the rate of the uncatalyzed reaction (k₁) is equal to the rate of the catalyzed reaction (k₂), we have:

$k_{1} = k_{2}$

$Ae^{\frac{-Ea_{1}}{RT_{1}}} = Ae^{\frac{-Ea_{2}}{RT_{2}}}$ (1)

By solving equation (1) for T₁ we have:

$T_{1} = \frac{T_{2}*Ea_{1}}{Ea_{2}} = \frac{293 K*70 kJ/mol}{42 kJ/mol} = 488. 33 K = 215.33 ^\circ C$

Therefore, we need to heat the solution at 215.33 °C so that the rate of the uncatalyzed reaction is equal to the rate of the catalyzed reaction.

I hope it helps you!

4 0

3 years ago

A certain liquid has a normal boiling point of and a boiling point elevation constant . A solution is prepared by dissolving som

Andrews [41]

The given question is incomplete. The complete question is as follows.

A certain liquid has a normal boiling point of $124.2^{o}C$ and a boiling point elevation constant $k_{b} = 0.62 ^{o}C kg mol^{-1}$ . A solution is prepared by dissolving some sodium chloride (NaCl) in 6.50 g of X. This solution boils at $127.4^{o}C$ . Calculate the mass of NaCl that was dissolved. Round your answer to significant digits.

Explanation:

As per the colligative property, the elevation in boiling point will be as follows.

T = boiling point of the solution =

$T_{o}$ = boiling point of the pure solvent = $124.2^{o}C$

$K_{b}$ = elevation of boiling constant = $0.62 ^{o}C kg mol^{-1}$

We will calculate the molality as follows.

molality = $\frac{\text{maas of solute}}{\text{molar mass of solute}} \times \frac{1000}{\text{mass of solvent in g}}$

i = vant hoff's factor

As NaCl is soluble in water and dissociates into sodium and chlorine ions so i = 2.

Putting the given values into the above formula as follows.

$T - T_{o} = i \times K_{b} \times \text{molality of solution}$

$(127.4 - 124.2)^{o}C = 2 \times 0.62 \times \frac{m}{60} \times \frac{1000}{650}$

m = 100 g

Therefore, we can conclude that 100 g of NaCl was dissolved.

3 0

3 years ago

Which of the following are likely to form an ionic bond?

Pani-rosa [81]

3) hydrogen and oxygen atoms forms water

6 0

3 years ago

Although I am in the middle of the 5 stages, I am just as important

erica [24]

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Explanation:

4 0

2 years ago