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Mazyrski [523]
2 years ago
9

A compound contains 81.1 boron with the remainder being hydrogen what is the empirical formula of the compound

Chemistry
1 answer:
kari74 [83]2 years ago
4 0
Empirical formula is the simplest ratio of whole numbers of components making up the compound
Mass percentage of boron - 81.1 %
Mass percentage of hydrogen - 18.9 %
For 100 g of the compound
                                               B                        H
Mass                                   81.1 g                  18.9 g
Number of moles          81.1 g /11 g/mol       18.9 g/1 g/mol
                                          = 7.37 mol             = 18.9 mol
Divide by the least number of moles
                                           7.37/7.37 =1.00     18.9/7.37 =2.56
Since we get 2.56 that cannot be rounded off we have to multiply both boron and hydrogen values by 2
B = 1.00 x2 = 2.00
H = 2.56 x 2 = 5.12 rounded off to 5
Therefore empirical formula is
B₂H₅

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A 63.5 g sample of an unidentified metal absorbs 355 ) of heat when its temperature changes
insens350 [35]

0.208 is the specific heat capacity of the metal.

Explanation:

Given:

mass (m)  = 63.5 grams 0R 0.0635 kg

Heat absorbed (q) = 355 Joules

Δ T (change in temperature) = 4.56 degrees or 273.15+4.56 = 268.59 K

cp (specific heat capacity) = ?

the formula used for heat absorbed  and to calculate specific heat capacity of a substance will be calculated by using the equation:

q = mc Δ T

c = \frac{q}{mΔ T}

c = \frac{355}{63.5X 268.59}

 = 0.208 J/gm K

specific heat capacity of 0.208 J/gm K

The specific heat capacity is defined as  the heat required to raise the temperature of a substance which is 1 gram. The temperature is in Kelvin and energy required is in joules.

 

5 0
2 years ago
2. If 2.50g of sodium hydroxide is being reacted with 4.30g of magnesium chloride, how many grams of magnesium hydroxide would b
Virty [35]

Answer:

1.822 g of magnesium hydroxide would be produced.

Explanation:

Balanced reaction: 2NaOH+MgCl_{2}\rightarrow Mg(OH)_{2}+2NaCl

     Compound                                 Molar mass (g/mol)

         NaOH                                           39.997

         MgCl_{2}                                           95.211

        Mg(OH)_{2}                                        58.3197

So, 2.50 g of NaOH = \frac{2.50}{39.997} mol of NaOH = 0.0625 mol of NaOH

      4.30 g of MgCl_{2}  = \frac{4.30}{95.211} mol of MgCl_{2} = 0.0452 mol of MgCl_{2}

According to balanced equation-

2 mol of NaOH produce 1 mol of Mg(OH)_{2}    

So, 0.0625 mol of NaOH produce (\frac{0.0625}{2}) mol of NaOH or 0.03125 mol of NaOH

1 mol of MgCl_{2} produces 1 mol of Mg(OH)_{2}

So, 0.0452 mol of MgCl_{2} produce 0.0452 mol of Mg(OH)_{2}

As least number of moles of Mg(OH)_{2} are produced from NaOH therefore NaOH is the limiting reagent.

So, amount of Mg(OH)_{2} would be produced = 0.03125 mol

                                                                           = (0.03125\times 58.3197) g

                                                                           = 1.822 g

6 0
2 years ago
If you fill up a balloon with a small amount of air, then set it in direct sunlight, you will see that the balloon expands. This
almond37 [142]
I just did guessed on the question and got it right. The answer is kinetic energy.
6 0
2 years ago
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What is the mass of 0.5 moles of carbon tetrafluoride, CF4?
VashaNatasha [74]

Answer:

44 g

Explanation:

The formula for the number of moles (n) is equal to n=\frac{mass}{molecular weight} .

Since we need to find the mass, we derive it from the formula of the number of moles and we get that mass = n x molecular weight .

The molecular weight of CF_{4} = 12 g/mol (from the carbon) + 19x4 g/mol (from the 4 fluorine atoms)= 88 g/mol

We plug in the numbers in the derived formula for the mass and we get :

mass = n x molecular weight = 0.5 mol x 88 g/mol = 44 g

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2 years ago
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Each of three identical 15.0-L gas cylinders contains 7.50 mol of gas at 295 K. Cylinder A contains Ne, cylinder B contains NO2,
FrozenT [24]

Answer:

d) All have identical pressures

Explanation:

The kinetic molecular theory explains how gas molecules behave in a container. By this theory, the gas particles behave like hard, spherical objects in a state of constant, random motion; these particles collide between them and at the walls of the container. Besides, the kinetic energy of the gas depends only on the temperature.

The pressure is the force that the particles are applying under some area, so by the theory, it depends on the number of moles (amount of particles that collides and make the force), the volume of the container and the kinetic energy, or the temperature.

Because all gases have the same number of moles and are at the same temperature and the same volume, they'll have the same pressure.

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2 years ago
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