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vredina [299]
3 years ago
11

Which will decrease the rate of a reaction?

Chemistry
2 answers:
zloy xaker [14]3 years ago
8 0

Answer:

(A) changing the temperature from 90ºC to 40ºC

Explanation:

;p

rusak2 [61]3 years ago
6 0

Explanation:

The reaction rate decreases with a decrease in temperature. Catalysts can lower the activation energy and increase the reaction rate without being consumed in the reaction. Differences in the inherent structures of reactants can lead to differences in reaction rates.

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For the following equilibrium system, which of the following changes will form more CaCO3? CO2(g) + Ca(OH)2(s) ⇌ CaCO3(s) + H2O(
Talja [164]

Answer: d. Remove one-half of the initial CaCO3.

Explanation: Le Chatelier's principle states that changes on the temperature, pressure, concentration and volume of a system will affect the reaction in an observable way. So in the reaction above:

A decrease in temperature will shift the equilibrium to the left because the reaction is exothermic, which means heat is released during the reaction. In other words, when you decrease temperature of a system, the equilibrium is towards the exothermic reaction;

A change in volume or pressure, will result in a production of more or less moles of gas. A increase in volume or in the partial pressure of CO2, the side which produces more moles of gas will be favored. In the equilibrium above, the shift will be to the left.

A change in concentration will tip the equilibrium towards the change: in this system, removing the product will shift the equilibrium towards the production of more CaCO3 to return to the equilibrium.

So, the correct answer is D. Remove one-half of the initial CaCO3.

8 0
4 years ago
Nicotine, a component of tobacco, is composed of c, h, and n. A 2.625-mg sample of nicotine was combusted, producing 7.1210 mg o
Vikki [24]

The mass sample of nicotine combusted = 2.625 mg  (given)

Mass of CO_2 produced = 7.1210 mg  (given)

Mass of H_2O produced = 2.042 mg  (given)

Molar mass of CO_2 = 44 g/mol

Molar mass of H_2O = 18 g/mol

Percentage of Carbon = \frac{12 g}{44 g/mol}\times \frac{7.120 mg of CO_2}{2.625 mg sample}\times 100 = 74.04%

Percentage of hydrogen = \frac{2 g}{18 g/mol}\times \frac{2.04 mg of H_2O}{2.625 mg sample}\times 100 = 8.62%

Now, for percentage of nitrogen = 100 - (74.04+8.62) = 17.34%

Calculating the moles of each element:

Number of moles = \frac{given mass}{Molar mass}

  • For C

\frac{74.04 g}{12 g/mol} = 6.17 mol

  • For H

\frac{8.62 g}{1 g/mol} = 8.62 mol

  • For N

\frac{17.34 g}{14 g/mol} = 1.24 mol

Dividing with the smallest mole value to calculate the molar ratio of each element:

C_{\frac{6.17}{1.24}} = C_{4.9} = C_5

H_{\frac{8.62}{1.24}} = H_{6.9} = H_7

N_{\frac{1.24}{1.24}} = N_1

Hence, the empirical formula for nicotine is C_5H_7N.

8 0
3 years ago
True or False. Physical changes result in the formation of a new substance.
Umnica [9.8K]

Answer:

1. false

2. true

Explanation:

I hope this helps

3 0
4 years ago
A gas in a cylinder with movable piston has an initial volume Of 88.2 ML at 35°C. The cylinder is heated at constant pressure un
Leona [35]
The  temperature  in  degree  celsius  to  which  the gas    was  heated  is  calculated  using the Charles  law   formula

that is  V1/T1 =V2/T2
V1=88.2 ml
T1=35 +273 = 308  K
V2=123 ml
T2=?

by  making T2  the formula of the  subject  T2=V2T1/V1

=(123 ml  x308 k)/88.2 ml =429.5 K

in  degree  celsius = 429.5  -273= 156.5  degree celsius
7 0
3 years ago
What happens to a liquid as it evaporates
guapka [62]
It turns into a gas when it evaporates
8 0
3 years ago
Read 2 more answers
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