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2 years ago

9

Why is the addition of cold distilled water to the container holding the aspirin you are trying to isolate a necessary step and

why should this step be carried out carefully?.

1 answer:

Rudik [331]2 years ago

3 0

Answer:

The aspirin is more soluble in ethanol than water - the water helps the crystals separate from solution.

Explanation:

Hope this helps!

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Any help with these questions would help i'm lost

SSSSS [86.1K]

Answer:

1. 31.25 mL

2. 1.98 g/L

3. 0.45 g/mL

Explanation:

For each of the problems, you need to perform unit conversions. You need to use the information given to you to convert to a specific unit.

1. You need volume (mL). You have density (g/mL) and mass (g). Divide mass by density. You will cancel out mL and be left with g.

(50.0 g)/(1.60 g/mL) = 31.25 mL

2. You are given grams and liters. You need to find density with units g/L. This means that you have to divide grams by liters.

(0.891 g)/(0.450 L) = 1.98 g/L

3. You have to find density again but this time with units g/mL. Divide the given mass by the volume.

(10.0 g)/(22.0 mL) = 0.45 g/mL

5 0

3 years ago

How many moles are in a 62.5-g sample of potassium nitrate (KNO3)?

Reil [10]

Answer:25.3 g of KNO₃ contain 0.25 moles.

Explanation:

7 0

3 years ago

maks197457 [2]

<u>Answer:</u> The mass of $H_2O$ produced is 2.52 g

<u>Explanation:</u>

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

<u>For hexane:</u>

Given mass of hexane = 1.72 g

Molar mass of hexane = 86.18 g/mol

Putting values in equation 1, we get:

$\text{Moles of hexane}=\frac{1.72g}{86.18g/mol}=0.020mol$

<u>For oxygen gas:</u>

Given mass of oxygen gas = 8.0 g

Molar mass of oxygen gas= 32 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{8.0g}{32g/mol}=0.25mol$

The chemical equation for the combustion of hexane follows:

$2C_6H_{14}+19O_2\rightarrow 12CO_2+14H_2O$

By stoichiometry of the reaction:

If 2 moles of hexane reacts with 19 moles of oxygen gas

So, 0.020 moles of hexane will react with = $\frac{19}{2}\times 0.020=0.19mol$ of oxygen gas

As the given amount of oxygen gas is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Thus, hexane is considered a limiting reagent because it limits the formation of the product.

By the stoichiometry of the reaction:

If 2 moles of hexane produces 14 moles of $H_2O$

So, 0.020 moles of hexane will produce = $\frac{14}{2}\times 0.020=0.14mol$ of $H_2O$

We know, molar mass of $H_2O$ = 18 g/mol

Putting values in above equation, we get:

$\text{Mass of }H_2O=(0.14mol\times 18g/mol)=2.52g$

Hence, the mass of $H_2O$ produced is 2.52 g

4 0

3 years ago

Which option states the principle behind the law of conservation of mass and the law of conservation of energy?

jeka94

Answer:

A

Explanation:

The law of conservation of mass states that matter can never be created nor destroyed but can be converted from one form to another.

The law of conservation of energy posits that energy cannot be created nor destroyed but can be converted from one form to another.

These laws are the basic laws of existence. Although the laws have been adjusted, they still form the basic principle behind several scientific laws and are responsible for a whole lot of scientific advancements.

While the first law focuses on matter and the content of matter in a body, the second law basically focuses on energy. The second law serves to support the inter convertibility behind the several forms or types of energy.

For example, to do many useful work at home, it is found that energy is converted from its electric form to say heat in an electric iron to press our clothes.

Also, the first law is a fundamental principle useful in the balancing of our chemical equations.

7 0

3 years ago

An ionic bond occurs between what particles

kakasveta [241]

<span>The correct answer is that an ionic bond forms between charged particles. To form this bond, the particles transfer valence electrons (those in the outermost orbit). Specifically, in ionic bonding, the metal atom loses its electrons (thus becoming positive) and the nonmetal atom gains electrons (thus becoming negative).</span>

4 0

3 years ago

Read 2 more answers