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3 years ago

Calculate the mass (in g) of solute needed to prepare a solution with the given concentration and volume.

Chemistry

1 answer:

sweet [91]3 years ago

3 0

Answer:

1. 35g NaCl.

2. 234g sugar.

3. 0.506L of concentrated nitric acid are needed.

4. 1.67L of 9.0M copper (II) sulfate are needed

Explanation:

Molarity is defined as the ratio between moles of solute and the volume of the solution.

1. 1.00L * (0.60mol / L) = 0.60 moles NaCl are dissolved

To convert moles to mass we must use its molar mass:

0.60mol NaCl * (58.44g/mol) =

35g NaCl

2. 2L * (0.342mol / L) = 0.684 moles Sugar = moles sucrose

0.684 mol * (342.30g / mol) = 234g sugar

3. 4L of a 2.0M are:

4L * (2.0mol/L) = 8moles

8mol * (1L / 15.8mol) = 0.506L of concentrated nitric acid are needed

4. 3.0L * (5.0 mol / L) = 15.0 moles copper (II) sulfate.

15.0mol * (1L / 9.0mol) = 1.67L of 9.0M copper (II) sulfate are needed

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A student wants to examine a substance by altering the bonds within its molecules. Which of the following properties of the subs

Marrrta [24]

Question is incomplete, the complete question is as follows:

A student wants to examine a substance by altering the bonds within its molecules. Which of the following properties of the substance should the student examine?

A. Toxicity, because it can be observed by altering the state of the substance

B. Boiling point, because it can be observed by altering the state of the substance

C. Toxicity, because it can be observed by replacing the atoms of the substance with new atoms

D. Boiling point, because it can be observed by replacing the atoms of the substance with new atoms

Answer:

Explanation:

A student can examine a substance without altering the bonds within the molecules by examining its boiling point.

The boiling point is the property of a substance, at which the substance changes its state, which is from solid to liquid, liquid to gas and others. So, examining the boiling point will alter the bonds within the molecules as the state of substance will change.

Hence, the correct answer is "B".

6 0

3 years ago

Compute 214.056 + 9.3456. Round the answer appropriately

shusha [124]

214.0560
+ 9.3456
=223.4016

3 0

2 years ago

All modern fertilizers use PO43- as a source of phosphorus. Use your knowledge of the old methods to determine the moles of phos

tamaranim1 [39]

Answer:

The answer is 0.023 moles of phosphorus

Explanation:

The 15-15-15 fertilizer is a fertilizer of great versatility, made with nitrogen, phosphorus and potassium, which makes it one of the fertilizers most used for fertilizer in the sowing plant, thus covering the crop requirements from planting. .

This fertilizer consists of 14.25% phosphorus pentoxide (P2O5). Therefore, we have to remove 14.25% at 10 grams of 15-15-15 fertilizer to calculate the moles of phosphorus. As follows:

Grams of P2O5 = 10 g x 0.1425 = 1.425 g

We calculate the molecular weight of phosphorus. We use the periodic table:

Phosphorus molecular weight = 2 x 30.97 = 61.94 g/mol

Now we calculate the moles of phosphorus in the fertilizer:

Phosphorus moles = 1,425 g/61.94 g/mol = 0.023 moles

8 0

2 years ago

You have just isolated a new radioactive element. If you can determine its half-life, you will win the Nobel Prize in physics. Y

lbvjy [14]

Answer: 2.58 days

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = ?

t = age of sample = 6 days

a = initial amount of the reactant = 1 g

a - x = amount left after decay process = 0.2 g

a) to find the rate constant

$6=\frac{2.303}{k}\log\frac{1.0}{0.2}$

$k=\frac{2.303}{6}\log\frac{1.0}{0.2}$

$k=0.268days^{-1}$

b) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

$t_{\frac{1}{2}}=\frac{0.693}{k}$

$t_{\frac{1}{2}}=\frac{0.693}{0.268}=2.58days$

The half life is 2.58 days

3 0

3 years ago

Which of the four substances listed will dissolve in water and why?

Orlov [11]

Answer:

Sugar, sodium chloride, and hydrophilic proteins are all substances that dissolve in water. Oils, fats, and certain organic solvents do not dissolve in water because they are hydrophobic.

And, water is called the "universal solvent" because it dissolves more substances than any other liquid. ... Water molecules have a polar arrangement of the oxygen and hydrogen atoms—one side (hydrogen) has a positive electrical charge and the other side (oxygen) had a negative charge.

I don't see any options so there i hope it helps .

7 0

3 years ago