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2 years ago

Please help!!

1 answer:

8 0

Molarity = Moles/Liter

Use the molecular atomic mass of NaCl to convert from grams to moles.
Molecular mass of NaCl is the sum of its atomic masses. Look at the periodic table to find these. Na is 23 g/mol and Cl is 35.5 g/mol ,
so NaCl = 23 + 35.5 = 58.5 g/mol

multiply to cancel out grams
76 g NaCl * (1mol / 58.5 g NaCl) = 1.3 mol NaCl

over 1 Liter is just 1.3 M NaCl
Hope this helps!

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You are holding four identical balloons each containing 10.0g of a different gas. The balloon containing which gas is the larges

Vaselesa [24]

Answer:

Hydrogen, H_2

Explanation:

mass of each gas is 10.0 g

number of mole = mass/ molar mass

number of moles is directly proportional to volume at constant temp and pressure

this implies that the volume is inversely proportional to molar mass. And Among all the gases in periodic table the molar mass of Hydrogen is the least.

molar mass of H2=2 g/mol

Since, H2 has minimum molar mass then for the same mass of the gases Hydrogen will have maximum volume.

6 0

2 years ago

Consider the solutions, 0.04 m urea [(NH2)2C=O)], 0.04 m AgNO3 and 0.04 m CaCl2. Which has (i) the highest osmotic pressure, (ii

Lana71 [14]

Answer:

i) Highest osmotic pressure: CaCl2

ii) lower vapor pressure : CaCl2

iii) highest boiling point : CaCl2

Explanation:

The colligative properties depend upon the number of solute particles in a solution.

The following four are the colligative properties:

a) osmotic pressure : more the concentration of the solute, more the osmotic pressure

b) vapor pressure: more the concentration of the solute, lesser the vapor pressure.

c) elevation in boiling point: more the concentration of the solute, more the boiling point.

d) depression in freezing point: more the concentration of the solute, lesser the freezing point.

the number of particle produced by urea = 1

the number of particle produced by AgNO3 = 2

the number of particle produced by CaCl2 = 3

As concentrations are same, CaCl2 will have more number of solute particles and urea will have least

i) Highest osmotic pressure: CaCl2

ii) lower vapor pressure : CaCl2

iii) highest boiling point : CaCl2

5 0

2 years ago

A voltaic cell that uses the reaction

love history [14]

Did you intend to write [PdCl4]^-2 instead of PdCl2-4? If so, then:

<span>Cathode: [PdCl4]^-2(aq) + 2e- ======⇒ Pd(s) + 4Cl-(aq) </span>

<span>Anode: Cd(s) ==⇒ Cd+2(aq) + 2e-</span>

4 0

2 years ago

A sample of 0.6760 g of an unknown compound containing barium ions (ba2+) is dissolved in water and treated with an excess of na

notka56 [123]

Answer: 35.72 % of Barium ions will be present in the original unknown compound.

Explanation: The reaction of Barium ions and sodium sulfate is:

$Na_2SO_4(aq.)+Ba^{2+}(aq.)\rightarrow BaSO_4(s)+2Na^+(aq.)$

Here, Sodium sulfate is present in excess, Barium ions are the limiting reagent because it limits the formation of product.

Now, 1 mole of barium sulfate is produced by 1 mole of Barium ions.

Molar mass of Barium sulfate = 233.38 g/mol

Molar mass of Barium ions = 137.327 g/mol

233.38 g/mol of barium sulfate will be produced by 137.323 g/mol of Barium ions, so

0.4105 grams of barium sulfate will be produced by = $\frac{137.327g/mol}{233.38g/mol}\times 0.4105g$ of Barium ions

Mass of barium ions = 0.2415 grams

To calculate percentage by mass, we use the formula:

$\% mass=\frac{\text{Mass of solute (in grams)}}{\text{Total mass of the solution(in grams)}}\times 100$

Mass of the solution = 0.6760 grams

Putting the value in above equation, we get

$\% \text{ mass of }Ba^{2+}\text{ ions}=\frac{0.2415g}{0.6760g}\times 100$

% mass of Barium ions = 35.72%.

8 0

2 years ago

4. a) The enthalpy change of combustion of hexane was measured using a calorimeter containing 200 cm3 of water; 0.5g of hexane (

mamaluj [8]

Answer:

The heat of combustion of hexane is -4324kjmol-1

Explanation:

Heat of combustion is the heat evolved when a mole of a substance is burned completely in oxygen under standard conditions.

To solve this problem, all the required values have been given.

Change in temperature ΔT = 30K

Mass of water =200cm3= 200g

Mass of Hexane burned = 0.5g

Step 1:

Find the amount of hear given off

Heat evolved= mass * specific eat capacity of water* temperature change

= 200 * 4.18 * 30

= 25080J

Step 2:

Calculate the relative molecular mass of hexane

RMM of C6H14 = 86g/mole.

Step 3:

Calculate the number of moles of Hexane burned

Numbrt of mole of hexane = mass / molar mass

n = 0.5 / 86

n = 0.0058mole

Step 4:

Calculate the enthalpy change of combustion for 1mole

Combustion of 0.0058mole hexane produces 25080J of heat energy

I mole hexane produces 25080 /0.0058

= 4324kJ of heat energy.

The enthalpy change of combustion of Hexane is -4,324kJmol-1.

There is no need to do anything else for the question.

7 0

2 years ago