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3 years ago

What does a catalyst do when added to a chemical reaction? Select all that apply.

Chemistry

2 answers:

Darina [25.2K]3 years ago

8 0

Answer:

$\boxed {\boxed {\sf It \ lowers \ the \ activation \ energy \ and \ it \ speeds \ up \ chemical \ reactions }}$

Explanation:

A catalyst is a substance that <u>increases the rate</u> of a chemical reaction. Some examples are enzymes and acid-base catalysts.

They can do this by <u>lowering activation energy</u> (the energy needed to undergo a reaction) or modifying a certain mechanism in the reaction.

Catalysts are unique because they aren't consumed or used up in a reaction. They can be reused many times.

So, based on the information above, catalysts do not increase the activation energy or get consumed in the reaction. That leaves two correct answers: they lower the activation energy and speed up chemical reactions.

Stels [109]3 years ago

7 0

Answer:

It increases the activation energy.

It speeds up chemical reactions.

Explanation:

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What is the volume of an object with a density of 2.6 g/cm³ and a mass of 30.5g?

inessss [21]

Answer:

The answer is

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

$volume = \frac{mass}{density}$

From the question

mass of object = 30.5 g

Density = 2.6 g/cm³

The volume is

$volume = \frac{30.5}{2.6} \\ = 11.7307692...$

We have the final answer as

Hope this helps you

5 0

3 years ago

What do methanol (CH2O), ethanoic acid (C2H4O2), and glucose (C3H6O3) all have in common?

tatyana61 [14]

Answer:

Explanation:

Carbohydrates are compounds containing carbon, hydrogen, and oxygen. Therefore, a is true.

An empirical formula is the simplest ratio of atoms present in a compound. Therefore, C2H4O2 and C3H6O3, (if you simplified them like you would a fraction) would be CH2O. Therefore b is correct,

They also have the same % composition, with a ratio of 1 carbon : 2 hydrogen : 1 oxygen. Therefore, c is correct.

Since a, b and c are all correct, the answer is d, all of the above are true.

6 0

3 years ago

Consider the titration of 1L of 0.36 M NH3 (Kb=1.8x10−5) with 0.74 M HCl. What is the pH at the equivalence point of the titrati

worty [1.4K]

Answer:

Explanation:

The question asks to calculate the pH at equivalence point of the titration between ammonia and hydrochloric acid

Firstly, we write the equation of reaction between ammonia and hydrochloric acid.

NH3(aq)+HCl(aq)→NH4Cl(aq)

Ionically:

HCl + NH3 ---> NH4 + Cl-

Firstly, we calculate the number of moles of the ammonia as follows:

from c = n/v and thus, n = cv = 0.36 × 1 = 0.36 moles

At the equivalence point, there is equal number of moles of ammonia and HCl.

Hence, volume of HCl = number of moles/molarity of HCl = 0.36/0.74 = 0.486L

Hence, the total volume of solution will be 1 + 0.486 = 1.486L

Now, we calculate the concentration of the ammonium ions = 0.36/1.486 = 0.242M

An ICE TABLE IS USED TO FIND THE CONCENTRATION OF THE HYDROXONIUM ION(H3O+). ICE STANDS FOR INITIAL, CHANGE AND EQUILIBRIUM.

NH4+ H2O ⇄ NH3 H3O+

I 0.242 0 0

C -X +x +X

E 0.242-X X X

Since the question provides us with the base dissociation constant value K b, we can calculate the acid dissociation constant value Ka

To find this, we use the mathematical equation below

K a ⋅ K b = K w

, where K w- the self-ionization constant of water, equal to

10 ^-14 at room temperature

This means that you have

K a = K w.K b = 10 ^− 14 /1.8 * 10^-5 = 5.56 * 10^-10

Ka = [NH3][H3O+]/[NH4+]

= x * x/(0.242-x)

Since the value of Ka is small, we can say that 0.242-x ≈ 0.242

Hence, K a = x^2/0.242 = 5.56 * 10^-10

x^2 = 0.242 * 5.56 * 10^-10 = 1.35 * 10^-10

x = 0.00001161895

[H3O+] = 0.00001161895

pH = -log[H3O+]

pH = -log[0.00001161895 ] = 4.94

7 0

3 years ago

Will mark as Brainliest.

postnew [5]

<span>0.453 moles O2 is the solution</span>

3 0

3 years ago

Read 2 more answers

Which orbital has the lowest energy

GalinKa [24]

Answer:

s orbital

Explanation:

it has the lowest energy because

Paulis law state that orbitals with lower energy must be fill first before that of higher energy

and the s orbital is filled first

5 0

3 years ago