ANSWER FAST PLZ 25 POINTS!!!!!!!!!!!!!!!!!

When doing a recrystallization what observations would prompt

Volgvan

<h2>Observation of purified crystals.</h2>

Explanation:

Recrystallization is the process in which a compound is dissolved in a hot solvent and then allowed to cool which forms the crystals.
It is a technique used for purification of solids.
Recrystallization mainly depends on the solubility of the solvent that means the solid should be soluble in the solvent when it is hot and should be insoluble in the same solvent when it is cool.
The observations while doing recrystallization is to observe the purified crystals obtained and to filter it out.

5 0

3 years ago

Classify each of the following substances:

Keith_Richards [23]

Explanation:

Carbon dioxide is a polar molecule whose positive center is on the carbon atom: This positive center is able to attract (and accept) the lone electron pairs present on the oxide ion (O2-). carbon dioxide is acts as a Lewis acid

A Lewis acid can accept a pair of electrons from a Lewis base. The boron in BF3 is electron poor and has an empty orbital, so it can accept a pair of electrons, making it a Lewis acid. A Lewis acid is defined as an electron-pair acceptor.

In CO molecule, there is a lone pair on both carbon and oxygen. The substance which can donate an electron pair are called Lewis base. It is clear that CO molecule can donate an electron pair and hence, it is a Lewis base. Also, CO can be BOTH a Lewis acid and base.

Oxygen is a Lewis base (that too a weak one), not a Lewis acid. REASON: It has lone pair of electrons, which can be donated to electron-deficient species (Lewis acids).

Methane is Neither a Lewis Acid or Lewis Base.

5 0

3 years ago

The following data was collected when a reaction was performed experimentally in the laboratory.

REY [17]

Answer:

The answer to your question is 3 moles of AlCl₃

Explanation:

Process

1.- Write and balance the equation

Al(NO₃)₃ + 3NaCl ⇒ 3NaNO₃ + AlCl₃

2.- Determine the limiting reactant

Theoretical proportion 1 mol Al(NO₃)₃ : 3 moles of NaCl

Experimental proportion 4 moles Al(NO₃)₃ : 9 moles NaCl

From these values, we determine that the limiting reactant is NaCl because the number of moles increases three times and the number of moles of Al(NO₃)₃ increases four times.

3.- Determine the amount of AlCl₃ using proportions

3 moles of NaCl --------------- 1 mol of AlCl₃

9 moles of NaCl ---------------- x

x = (9 x 1) / 3

x = 9 /3

x = 3 moles

5 0

3 years ago

What are the mole fraction and the mass percent of a solution made by dissolving 0.21 g KBr in 0.355 L water? (d = 1.00 g/mL.) m

IRISSAK [1]

Answer:

Mol fraction H2O = 0.99991

Mol fraction KBr = 0.00009

mass % KBr = 0.059 %

mass % H2O = 99.941 %

Explanation:

Step 1: Data given

Mass of KBr = 0.21 grams

Molar mass KBr = 119 g/mol

Volume of water = 355 mL

Density of water = 1.00 g/mL

Molar mass water = 18.02 g/mol

Step 2: Calculate mass water

Mass water = 355 mL * 1g /mL

Mass water = 355 grams

Step 3: Calculate moles water

Moles water = mass water / molar mass water

Moles water = 355 grams / 18.02 g/mol

Moles water = 19.7 moles

Step 4: Calculate moles KBr

Moles KBr = 0.21 grams / 119 g/mol

Moles KBr = 0.00176 moles

Step 5: Calculate total moles

Total moles = 19.7 moles + 0.00176 moles

Total moles = 19.70176 moles

Step 6: Calculate mol fraction

Mol fraction H2O = 19.7 moles / 19.70176 moles

Mol fraction H2O = 0.99991

Step 7: Calculate mol fraction KBr

Mol fraction KBr = 0.00176 / 19.70176

Mol fraction KBr = 0.00009

Step 6: Calculate mass %

mass % KBR = (0.21 grams / (0.21 + 355) grams) *100%

mass % KBr = 0.059 %

mass % H2O = (355 grams / 355.21 grams) *100%

mass % H2O = 99.941 %

8 0

3 years ago

Tengo que resolver con procedimiento

zzz [600]

Answer:

Distance = 200 km

Distance = 204 km

Speed = 77 km/h

Time = 21.42 h

Explanation:

Given:

A.

Speed = 100 km/h , Time = 2 h

Find:

Distance

B.

Speed = 68 km/h , Time = 3 h

Find:

Distance

C.

Distance = 154 km , Time = 2 h

Find:

Speed

D.

Distance = 1500 km speed = 70 km/h

Find:

Time

Computation:

Speed = distance / time

A.

Distance = 100 x 2

Distance = 200 km

B.

Distance = 68 x 3

Distance = 204 km

C.

Speed = 154 / 2

Speed = 77 km/h

D.

Time = 1500 / 70

Time = 21.42 h

6 0

3 years ago