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3 years ago

Which statement best describes the amount of catalyst that remains at the end of a reaction?

2 answers:

7 0

I believe the correct answer is C. The amount of catalyst is the same at the end as at the beginning of the reaction. Catalysts can't be consumed by the reaction thus is not D.

gizmo_the_mogwai [7]3 years ago

6 0

Answer is: C) The amount of catalyst is the same at the end as at the beginning of the reaction.

A catalyst is a chemical species that is present at the beginning of a reaction and reappears at the end.

An intermediate forms during the reaction and disappears before the end.

Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst.

Reactions occur faster with a catalyst because they require less activation energy.

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A 51.9g sample of iron, which has a specific heat capacity of 0.449·J·g?1°C?1, is put into a calorimeter (see sketch at right) t

Ghella [55]

Answer:

the initial temperature of the iron sample is Ti = 90,36 °C

Explanation:

Assuming the calorimeter has no heat loss to the surroundings:

Q w + Q iron = 0

Also when the T stops changing means an equilibrium has been reached and therefore, in that moment, the temperature of the water is the same that the iron ( final temperature of water= final temperature of iron = T )

Assuming Q= m*c*( T- Tir)

mc*cc*(T-Tc)+mir*cir*(T - Tir) = 0

Tir = 20.3 °C + 300 g * 4.186 J/g°C * (20.3 C - 19 °C) / ( 51.9 g * 0.449 J/g°C )

Tir = 90.36 °C

Note :

- The specific heat capacity of water is assumed 1 cal/g°C = 4.186 J/g°C

- We assume no reaction between iron and water

7 0

4 years ago

In what ways do scientists not study the history of Earth's climate?

BARSIC [14]

(A) Studying ice cores

3 0

3 years ago

For the equilibrium

Mamont248 [21]

Answer:

Equilibrium concentrations of the gases are

$H_2S=0.596M$

$H_2=0.004 M$

$S_2=0.002 M$

Explanation:

We are given that for the equilibrium

$2H_2S\rightleftharpoons 2H_2(g)+S_2(g)$

$k_c=9.0\times 10^{-8}$

Temperature, $T=700^{\circ}C$

Initial concentration of

$H_2S=0.30M$

$H_2=0.30 M$

$S_2=0.150 M$

We have to find the equilibrium concentration of gases.

After certain time

2x number of moles of reactant reduced and form product

Concentration of

$H_2S=0.30+2x$

$H_2=0.30-2x$

$S_2=0.150-x$

At equilibrium

Equilibrium constant

$K_c=\frac{product}{Reactant}=\frac{[H_2]^2[S_2]}{[H_2S]^2}$

Substitute the values

$9\times 10^{-8}=\frac{(0.30-2x)^2(0.150-x)}{(0.30+2x)^2}$

By solving we get

$x\approx 0.148$

Now, equilibrium concentration of gases

$H_2S=0.30+2(0.148)=0.596M$

$H_2=0.30-2(0.148)=0.004 M$

$S_2=0.150-0.148=0.002 M$

3 0

3 years ago

Name two compounds in unpolluted air?

elena-14-01-66 [18.8K]

The two compounds present in unpolluted air are carbon dioxide and water. You may think that carbn dioxide is a greenhouse gas, yes it is and at the same time not. There animals in the earth that produces carbon dioxide into the atmosphere, the carbon dioxide too, is also need for plan respiration.

3 0

3 years ago

Using the model of the Periodic Table, which two elements pictured have similar chemical properties?

liberstina [14]

Answer:

C) 1 and 3

Explanation:

A period in the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. ... Arranged this way, groups of elements in the same column have similar chemical and physical properties, reflecting the periodic law.

5 0

3 years ago