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3 years ago

What is the number of moles of solute in a .3 molality solution containing .10 kg of solvent?

Chemistry

2 answers:

Dominik [7]3 years ago

8 0

Answer:

0.03

Explanation:

denpristay [2]3 years ago

4 0

Concentration can be expressed in different forms: molarity, molality, normality, percentage, part per million and many more. For molality, it is a unit of concentration expressed as moles of solute per kilogram of solvent. Therefore,

0.3 = moles solute/0.10 kg solvent
moles solute = 0.03 moles

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Describe happens when you move any atom toward the positive nuclear charge.

bekas [8.4K]

Answer:

Across a period, effective nuclear charge increases as electron shielding remains constant. A higher effective nuclear charge causes greater attractions to the electrons, pulling the electron cloud closer to the nucleus which results in a smaller atomic radius. ... This results in a larger atomic radius.

Explanation:

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2 years ago

Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid-fuel ro

melamori03 [73]

Answer: The mass of nickel (II) oxide and aluminium that must be used is 18.8 g and 4.54 g respectively.

Explanation:

To calculate the number of moles, we use the equation:

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

For nickel:

Given mass of nickel = 14.8 g

Molar mass of nickel = 58.7 g/mol

Putting values in equation 1, we get:

$\text{Moles of nickel}=\frac{14.8g}{58.7g/mol}=0.252mol$

For the given chemical reaction:

$3NiO(s)+2Al(s)\rightarrow 3Ni(l)+Al_2O_3(s)$

For nickel (II) oxide:

By Stoichiometry of the reaction:

3 moles of nickel are produced from 3 moles of nickel (II) oxide

So, 0.252 moles of nickel will be produced from $\frac{3}{3}\times 0.252=0.252mol$ of nickel (II) oxide

Now, calculating the mass of nickel (II) oxide by using equation 1:

Molar mass of nickel (II) oxide = 74.7 g/mol

Moles of nickel (II) oxide = 0.252 moles

Putting values in equation 1, we get:

$0.252mol=\frac{\text{Mass of nickel (II) oxide}}{74.7g/mol}\\\\\text{Mass of nickel (II) oxide}=(0.252mol\times 74.7g/mol)=18.8g$

For aluminium:

By Stoichiometry of the reaction:

3 moles of nickel are produced from 2 moles of aluminium

So, 0.252 moles of nickel will be produced from $\frac{2}{3}\times 0.252=0.168mol$ of aluminium

Now, calculating the mass of aluminium by using equation 1:

Molar mass of aluminium = 27 g/mol

Moles of aluminium = 0.168 moles

Putting values in equation 1, we get:

$0.168mol=\frac{\text{Mass of aluminium}}{27g/mol}\\\\\text{Mass of aluminium}=(0.168mol\times 27g/mol)=4.54g$

Hence, the mass of nickel (II) oxide and aluminium that must be used is 18.8 g and 4.54 g respectively.

4 0

3 years ago

Aluminum boils at 2467°C. Aluminum’s boiling point in Kelvin is 2194. T or F

dusya [7]

That is false because aluminum melts at 2,470C

7 0

3 years ago

A bar of soap is 12 cm long, 6 cm wide, and 10 cm long. It has a mass of 415 grams. What is the density of the bar of soap?

algol [13]

Density= mass/volume. volume= 12 x 6 x 10. 415/720=.57g/cm^3

4 0

3 years ago

What is the molar concentration of 35 mL of H2SO4 that neutralizes 25 mL of 0.320M NaOH

stira [4]

V ( H2SO4) = 35 mL / 1000 => 0.035 L

M ( H2SO4) = ?

V ( NaOH ) = 25 mL / 1000 => 0.025 L

M ( NaOH ) = 0.320 M

number of moles NaOH:

n = M x V

n = 0.025 x 0.320 => 0.008 moles of NaOH

Mole ratio:

2 NaOH + H2SO4 = Na2SO4 + 2 H2O

2 moles NaOH ---------------------- 1 mole H2SO4
0.008 moles moles NaOH ---------- ??

0.008 x 1 / 2 => 0.004 moles of H2SO4 :

Therefore:

M ( H2SO4) = n / V

M = 0.004 / 0.035

= 0.114 M

hope this helps!

6 0

3 years ago