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3 years ago

8

When a chemical is in the gaseous state, it has definite mass, but its shape is independent of the shape of the container in whi

ch it is stored?

1 answer:

Norma-Jean [14]3 years ago

5 0

Gaseous matter has no definite shape because the particles are packed so loosely and are very energetic, moving a lot.

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13,000. cm has how many significant figures?

Svet_ta [14]

Answer:

since there is a decimal point at the end, they are all significant figures so the answer is 5

5 0

3 years ago

Read 2 more answers

4.8 moles of Kl are dissolved in 850 mL of water. What is the molarity of the solutions?

AURORKA [14]

Hey there!

Molarity = 4.8/850 x 1000 =5.647mol/lit or 5.65M

Hope this helps you dear :)
Have a good day :)

4 0

2 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:

C

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

"What volume of" a 0.300 M BaF2 "solution is needed to prepare" 240.0 mL of a 0.100 M F- solution

zhannawk [14.2K]

Use M x V = M' x V'

0.300 x V = 0.100 x 250

V = .......... ml

6 0

3 years ago

Which term is used to describe the reactant that is used up completely and controls the amount of product that can be produced d

givi [52]

Answer: Option (c) is the correct answer.

Explanation:

A limiting reagent is defined as a reagent that completely gets consumed in a chemical reaction. A limiting reagent limits the formation of products.

For example, we have given 5 mol of A and the reaction is $2A + 4B \rightarrow 2AB$

Whereas when 4 mol B will react with 2 mol of A. Hence, 8 mol of B will react with 4 mol A as follows.

$\frac{2}{4} \times 8$ = 4 mol

As, the given moles of A is more than the required moles. Thus, it is considered as an excess reagent.

Hence, B is a limiting reagent because it limits the formation of products.

Thus, we can conclude that limiting reactant is the term used to describe the reactant that is used up completely and controls the amount of product that can be produced during a chemical reaction.

6 0

3 years ago