All categories

2 years ago

Please answer, please answer please answer please answermy last 2 chemistry question.

Chemistry

1 answer:

scoundrel [369]2 years ago

7 0

Answer:

1. filtration and evaporation

2. i) water is added to the sand and salt mixture

ii) then the mixture is filtrated and so the sand and the salt water was seperated

iii) the salt water is heated with the help of burner until the water gets evaporated

iv) after the water gets evaporated, the salt is remained in the container

3. observation:

on adding water to the mixture, the salt is completely dissolved in the water
when filtrated the sand is seperated from the salt water
now the salt water when heated with the burner until the evaporation, the water is evaporated
the salt is precipitated and remained in the container

4. cautions:

while using the burner, we should be cautious with fire
the container that is heated should be holded with the help of a cloth to avoid heat

You might be interested in

A sample of a food label is shown below.

White raven [17]

Answer:

A) It's correctly written

B) 77%

C) 835 calories

Explanation:

A) From online sources, we have number of calories as follows;

Fats: 9 calories per gram

Protein; 4 calories per gram

Carbs; 4 calories per gram

Total calories for each;

Total fat = 3 × 9 = 27 calories

Total protein = 3 × 4 = 12 calories

Total carbs = 32 × 4 = 128 calories

(sugar and dietary Fibre are classified as carbohydrates and so total carbs takes care of their calories).

Thus, total number of calories per serving = 27 + 12 + 128 = 167 calories per serving which is same as what is given.

B) percent from carbohydrates per serving = total calories from carbs/total number of calories per serving × 100% = 128/167 × 100% ≈ 77%

C) One box contains 5 servings. Thus total number of calories per box = 167 × 5 = 835 calories

8 0

3 years ago

140000 rounded to 3 sig gigs

attashe74 [19]

1.40E+5 (140000)
I believe this is right

8 0

3 years ago

An analytical chemist is titrating of a solution of propionic acid with a solution of 224.9 ml of a 0.6100M solution of propioni

Svetllana [295]

Answer: The pH of acid solution is 4.58

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in mL)}}$ .....(1)

For KOH:

Molarity of KOH solution = 1.1000 M

Volume of solution = 41.04 mL

Putting values in equation 1, we get:

$1.1000M=\frac{\text{Moles of KOH}\times 1000}{41.04}\\\\\text{Moles of KOH}=\frac{1.1000\times 41.04}{1000}=0.04514mol$

For propanoic acid:

Molarity of propanoic acid solution = 0.6100 M

Volume of solution = 224.9 mL

Putting values in equation 1, we get:

$0.6100M=\frac{\text{Moles of propanoic acid}\times 1000}{224.9}\\\\\text{Moles of propanoic acid}=\frac{0.6100\times 224.9}{1000}=0.1372mol$

The chemical reaction for propanoic acid and KOH follows the equation:

$C_2H_5COOH+KOH\rightarrow C_2H_5COOK+H_2O$

Initial: 0.1372 0.04514

Final: 0.09206 - 0.04514

Total volume of solution = [224.9 + 41.04] mL = 265.94 mL = 0.26594 L (Conversion factor: 1 L = 1000 mL)

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

$pH=pK_a+\log(\frac{[\text{salt}]}{[acid]})$

$pH=pK_a+\log(\frac{[C_2H_5COOK]}{[C_2H_5COOH]})$

We are given:

$pK_a$ = negative logarithm of acid dissociation constant of propanoic acid = 4.89

$[C_2H_5COOK]=\frac{0.04514}{0.26594}$

$[C_2H_5COOH]=\frac{0.09206}{0.26594}$

pH = ?

Putting values in above equation, we get:

$pH=4.89+\log(\frac{(0.04514/0.26594)}{(0.09206/0.26594)})\\\\pH=4.58$

Hence, the pH of acid solution is 4.58

7 0

3 years ago

Read the selection from the section "Molecules In Motion." The molecules in the hot soup are traveling faster overall than they

Hoochie [10]

Answer: The author used the word "conversely" because the first statement he made is in CONTRAST to the second statement he made.

Explanation:

Matter is made up of atoms or molecules that are in constant motion. The motion of these tiny particles ( molecules) gives the object energy. The movement of these molecules depends on the state of matter which includes

--> GASEOUS STATE: Here, the particles are completely free to move and are always in motion.

--> LIQUID STATE: particles in this state slide by one another and are always in motion.

--> SOLID STATE: particles in this state are held tightly together but are always in motion.

Also, the molecules in motion are greatly affected by temperature changes. Increase in temperature will cause the particles in the liquid to move faster. Such is seen when soup is heated, the molecules travel faster than before. But the OPPOSITE is seen in an ice cube. This is because the ice cube is in solid state and of a lower temperature.

7 0

2 years ago

isotopes of an element have the same number of protons but a different number of neutrons below u will see the nucleus of four d

dexar [7]

What is your question? Its not clear

3 0

3 years ago

Please answer, please answer please answer please answermy last 2 chemistry question. ​

Please answer, please answer please answer please answermy last 2 chemistry question.