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3 years ago

A sample of silver (Ag) contains 3.011x1023 atoms. How much does this

Chemistry

1 answer:

Ugo [173]3 years ago

3 0

Answer:

53.93 g Ag

Explanation:

3.011x1023 atoms Ag x 1 mole Ag x 107,8683 grams =

6.022x $10^{23}$ atoms 1 mole Ag

use the periodic table fo find Ag atomic mass and use Avogadro´s number

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A 20.0 ml sample of glycerol has a mass of 25.2 grams. What is the mass of 63 ml sample of glycerol?

poizon [28]

The mass of 63 ml sample : 79.38 g

<h3>Further explanation</h3>

Given

20 ml and 25.2 g of glycerol

Required

The mass of 63 ml sample

Solution

Density is the ratio of mass per unit volume

Density formula:

$\large{\boxed {\bold {\rho~=~ \frac {m} {V}}}}$

Density of glycerol :

= m : V

= 25.2 g : 20 ml

= 1.26 g/ml

Mass of 63 ml sample :

= density x volume

= 1.26 g/ml x 63 ml

= 79.38 g

7 0

3 years ago

Many double-displacement reactions are enzyme-catalyzed via the "ping pong" mechanism, so called because the reactants appear to

zhenek [66]

Answer:

D. It will decrease by a factor of 4

Explanation:

According to the question , the equation follows :

$A+B\rightarrow C+D$

Rate law : This states the rate of reaction is directly proportional to concentration of reactants with each reactant raised to some power which may or may not be equal to the stoichiometeric coefficient.

$Rate\ \alpha [A]^{a}[B]^{b}$

$r=[A]^{a}[B]^{b}$ .................(1)

STEP": First, find out the power "a" and "b"

a+b = 3 (because it is given that the reaction follow 3rd order-kinetics)

According to question, doubling the concentration of the first reactant causes the rate to increase by a factor of 2 means,

r' = 2r if [A'] = 2[A]

Here [B] is uneffected means [B']=[B]

hence new rate =

$r'=[A']^{a}[B']^{b}$

Put the value of [A'] , [B'] and r' in the above equation:

$2r=[2A]^{a}[B]^{b}$ ...........(2)

Divide equation (1) by (2) we , get

$\frac{2r}{r}=\frac{[2A]^{2}[B]^{b}}{[A]^{a}[B]^{b}}$

$2= 2(\frac{A}{A})^{a}\times (\frac{B}{B})^{b}$

Here A and A cancel each other

B and B cancel each other

We get,

$2= 2^{a}\times 1^{b}$

1^b = 1 ( power of 1 = 1)

$2= 2^{a}$

This is possible only when a = 1

We know that : a + b = 3

1 + b = 3

b =3 -1 = 2

b = 2

Hence the rate law becomes :

$r=[A]^{a}[B]^{b}$

$r=[A]^{1}[B]^{2}$ .............(3)

Look in the question now, it is asked to calculate the concentration of [B],if cut in half

Hence

[B']=1/2[B]

Insert the value of [B'] in equation (3)

$r'=[A]^{1}[B']^{2}$

$r'=[A]^{1}(\frac{1}{2}[B])^{2}$

$r'=\frac{1}{4}[A]^{1}[B]^{2}$ ............(a)

But

$r=[A]^{a}[B]^{b}$ ..............(b)

Compare equation (a) and (b) , we get

new rate r' =

r' = 1/4 r

7 0

3 years ago

In the chamber below, the volume is 20.5 L. What would the volume be if the temperature is increased to 500 K, the moles are red

grandymaker [24]

Answer:

C. bc I ssid

Explanation:

0+0+0+0+0+0=00

3 0

3 years ago

Read 2 more answers

Why is it preferable to allow cold water to enter at the bottom of a condenser and exit at the top?

harkovskaia [24]

In a distillation model, it is better to let the cold water enter the bottom of the condenser and exit at the top because this can lead to a better cooling effect.
When water enters from the bottom, they will stay longer in the condenser, thus the vapor in the condenser can be cooled back into liquid faster.
In addition, this method can also save the amount of water used, since they water can stay longer in the condenser.

5 0

4 years ago

How many moles of malachite should be formed when 1.5 moles of copper sulphate reacts with an excess of sodium carbonate?

Katen [24]

2 Na₂CO₃ + 2 CuSO₄ + H₂O → CuCO₃.Cu(OH)₂ + 2 Na₂SO₄ + CO₂
Malachite molar mass = 221.1 g / mol
So 2 moles CuSO₄ produce 1 mole of malachite
so 1.5 mole CuSO₄ produce (0.75) mole malachite
Mass of malachite = 0.75 mole * 221.1 g/ mol = 165.83 g

5 0

3 years ago