What percentage of the formula mass of Na2SO4 does sodium constitute?

How many moles are present in

olasank [31]

Answer: (a) There are 0.428 moles present in 12 g of $N_{2}$ molecule.

(b) There are 2 moles present in $12.044 \times 10^{23}$ particles of oxygen.

Explanation:

(a). The mass of nitrogen molecule is given as 12 g.

As the molar mass of $N_{2}$ is 28 g/mol so its number of moles are calculated as follows.

$No. of moles = \frac{mass}{molar mass}\\= \frac{12 g}{28 g/mol}\\= 0.428 mol$

So, there are 0.428 moles present in 12 g of $N_{2}$ molecule.

(b). According to the mole concept, 1 mole of every substance contains $6.022 \times 10^{23}$ atoms.

Therefore, moles present in $12.044 \times 10^{23}$ particles are calculated as follows.

$Moles = \frac{12.044 \times 10^{23}}{6.022 \times 10^{23}}\\= 2 mol$

So, there are 2 moles present in $12.044 \times 10^{23}$ particles of oxygen.

4 0

2 years ago

A compound is found to contain 38.65 % carbon, 16.25 % hydrogen, and 45.09 % nitrogen by mass. what is the empirical formula for

iren [92.7K]

The molar mass of carbon is 12, hydrogen is 1, and nitrogen is 14, hence the ratio are:

C = 38.65 / 12 = 3.22

H = 16.25 / 1 = 16.25

N = 45.09 / 14 = 3.22

Divide the three by the lowest ratio which is 3.22:

C = 3.22 / 3.22 = 1

H = 16.25 / 3.22 = 5

N = 3.22 / 3.22 = 1

So the empirical formula is:

CHN

5 0

2 years ago

A bottle of the antiseptic hydrogen peroxide is labeled 3.0% (v/v). How many mL of hydrogen peroxide are in a 400 mL bottle of t

zepelin [54]

There are several ways of expressing concentration of solution. Few of them are listed below
1) mass percentage
2) volume percentage
3) Molarity
4) Normality
5) Molality

In most of the drugs, concentration is expressed either in terms of mass percentage or volume percentage. For, solid in liquid type systems, mass percentage is convenient way of expressing concentration, while for liquid in liquid type solutions, expressing concentration in terms of volume percentage is preferred. Present system is an example of liquid in liquid type solution

Here, concentration of H2O2 is given antiseptic = 3.0 % v/v

It implies that, 3ml H2O2 is present in 100 ml of solution

Thus, 400 ml of solution would contain 4 X 3 = 12 ml H2O2

3 0

3 years ago

Select the best single answer. Which of the following accurately lists compounds in order of increasing solubility in water? LiC

Ann [662]

Answer:

The Correct increasing order of solubility is O2 < Br2 < LiCl < Methanol (CH3OH)

Explanation:

Solubility of compounds or molecules are solely dependent on its inter molecular forces or bonding present in them.

Molecules with Hydrogen bonding usually very soluble in water. Ionic compounds are also very soluble in water because they form ions in solutions. Molecules that possess van der waal forces are usually insoluble in water because they are non-polar.

O2 (oxygen gas) and Br2 (bromine gas) have van der waal forces in them. Van der waal forces are stronger in Br2 (bromine gas) than O2 (oxygen gas) because Br2 has more number of electrons.

LiCl is ionic in nature which makes it dissolve in water readily. it easily forms its ions (Li+ and Cl- ) in solutions.

Methanol (CH3OH) has the highest solubility in water compared to LiCl, Br2 and O2 because it contains Hydrogen bonding which is strongest of all inter molecular forces.

4 0

2 years ago

The chemical formula for table sugar is C 12 H 11 O 22 . What can you tell from this formula?

Paraphin [41]

The the last one, but isn't it c6h12o6?

8 0

3 years ago