1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Rashid [163]
3 years ago
11

Bonsoir les amis ,demain j'ai un examen de chimie en solution et je veux bien que vous m'aider à faire ce exercice s'il vous pla

it
calculer la qantite de NACL et de l'eau nécessaire pour l'obtention de 250g solution de NACL avec le pourcentage massique 10%
Chemistry
1 answer:
Leto [7]3 years ago
5 0

Dans 250 g de solution il y a 250×0,1 = 25g de chlorure de sodium.

Masse d'eau: 250g-25g = 225 g

masse volumique de l'eau 1 g cm-3 ; volume d'eau : 225 mL.



You might be interested in
In chemistry lab student is determining the salinity of seawater using a conductivity meter. The student made standards of NaCl
dimaraw [331]

Answer:

a. is an excel document. i uploaded as an attachment

b. concentration = 0.327

Explanation:

in the graph i uploaded for answer a, the x variable is conductivity,  while the y variable is % salinity.

the calculated regression line was calculated using excel =

y = 0.057655X - 0.00891

for answer part b,

we take x = 5.82

when we put this into the y formular

y = 0.057655(5.82) - 0.00891

y = 0.3355521 - 0.00891

y = 0.3266421

this is ≈ 0.327

in conclusion, using the standard curve, the concentration of unknown salt is 0.327. the % salinity = 0.327

6 0
3 years ago
What are the uses of chemistry? ​
devlian [24]

Answer:

Chemistry is the study of matter , its properties,how and why substance combine or separate to form other substance.

It's uses are

1) It is used in health care and beauty

2) Industries and transportation

3) Agriculture, science and technology

4) Cooking , cleaning, medicines etc

4 0
3 years ago
A 150 mL of oxygen gas is collected over water at 20 °C and 758 torr. What volume will the same sample of oxygen occupy at STP w
Stella [2.4K]

Answer:

The volume would be; 136.17 ml

Explanation:

Volume V1 = 150 mL

Temperature T1 = 20°C + 273 = 293 K

Pressure  P1 = 758 - 17.54 = 740.46 torr

At STP;

Volume V2 = ?

Pressure P2 = 760 torr

Temperature T2 = 273 K

Using the general gas equation;

P1V1 / T1   = P2V2 / T2

Making V2 subject of formulae;

V2 = P1V1T2 / T1P2

Inserting the values we have;

V2 = 740.46 * 150 * 273  /  293 * 760

V2 = 136.17 ml

3 0
3 years ago
5. By approximately what factor would the mass of a sample of copper-66
Fed [463]
That’s picture right there should help u with your works

7 0
3 years ago
Read 2 more answers
Calculate the pH and fraction of dissociation ( α ) for each of the acetic acid ( CH 3 COOH , p K a = 4.756 ) solutions. A 0.002
marysya [2.9K]

Answer:

The degree of dissociation of acetic acid is 0.08448.

The pH of the solution is 3.72.

Explanation:

The pK_a=4.756

The value of the dissociation constant = K_a

pK_a=-\log[K_a]

K_a=10^{-4.756}=1.754\times 10^{-5}

Initial concentration of the acetic acid = [HAc] =c = 0.00225

Degree of dissociation = α

HAc\rightleftharpoons H^++Ac^-

Initially

c

At equilibrium ;

(c-cα)                                cα        cα

The expression of dissociation constant is given as:

K_a=\frac{[H^+][Ac^-]}{[HAc]}

1.754\times 10^{-5}=\frac{c\times \alpha \times c\times \alpha}{(c-c\alpha)}

1.754\times 10^{-5}=\frac{c\alpha ^2}{(1-\alpha)}

1.754\times 10^{-5}=\frac{0.00225 \alpha ^2}{(1-\alpha)}

Solving for α:

α = 0.08448

The degree of dissociation of acetic acid is 0.08448.

[H^+]=c\alpha = 0.00225M\times 0.08448=0.0001901 M

The pH of the solution ;

pH=-\log[H^+]

=-\log[0.0001901 M]=3.72

3 0
4 years ago
Other questions:
  • What are salt ? How they are used
    11·1 answer
  • | What is frequency of a .002m long wave traveling at 330 m/s
    13·1 answer
  • Why are metals classified as conductors of electrical energy
    7·2 answers
  • 4. What is the percent yield of a reaction that produces 12.5 g CF2Cl2 from 32.9 g of CCl4 and excess HF
    13·1 answer
  • What is the mass of 2.30x10^22 formula units of NaOH (molar mass =40.0g/mol)
    6·1 answer
  • Which one is the correct answer <br> Thanks
    6·2 answers
  • What is a molecule??
    13·1 answer
  • FREE POINTS<br><br> DONT FORGET TO GIVE A HEART ON MY ACCOUNT HELPS
    12·2 answers
  • What is the name of these 4 compound in isomers​
    10·1 answer
  • Use the Lewis model to determine the formula for the compound that forms from each pair of atoms.
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!