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2 years ago

7. How many formula units are equal to a 0.25 g sample of Chromium (III) sulfate,

Chemistry

1 answer:

ryzh [129]2 years ago

7 0

Answer:

38.541 × 10¹⁹ formula units

Explanation:

Given data:

Mass of chromium sulfate = 0.25 g

Formula units in 0.25 g = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ formula units of water

Number of moles of chromium sulfate = Mass / molar mass

Number of moles of chromium sulfate = 0.25 g/ 392.16 g/ mol

Number of moles of chromium sulfate = 6.4 × 10⁻⁴ moles

Number of formula units:

1 mole = 6.022 × 10²³ formula units

6.4 × 10⁻⁴ moles × 6.022 × 10²³ formula units / 1 mol

38.541 × 10¹⁹ formula units

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A student assistant is cleaning up after a chemistry laboratory exercise and finds three one-liter bottles containing alcohol so

Svetllana [295]

The approximate alcohol content is 210 ml.

Explanation:

It can be deduced from the question that each bottle is of 1000ml or 1 litre.

The first bottle is one half full means it has 500 ml of solution and it has 20% alcohol in it. So volume of alcohol in the solution is

20/100*500

=100 ml

The first bottle is one fifth full, so the volume of mixture is 1/5th of 1000ml

so it is 200ml having 30% alcohol

30/100*200

= 60 ml

The third bottle is one tenth full so its volume is 1/10*1000

100 ml. having 50% of alcohol

50/100*100

50 ml.

The alcohol content obtained from all these 3 litres is:

100+60+50

= 210 ml of alchohol is obtained from 800 ml of mixture.

3 0

2 years ago

What mass of methanol is combusted in a reaction that produces 112 L of Co2 at STP?

AlekseyPX

Answer

D 160g

Explanation:

Write the equation:

Combustion reactions use oxygen and release water and heat, so

CH₃OH(g) + O₂(g) → CO₂(g) + H₂O(g)

Balance that:

2CH₃OH(g) + 3O₂(g) → 2CO₂(g) + 4H₂O(g)

Find moles of carbon dioxide:

We need to know the number of moles of CO₂. This rxn is at STP, so at STP one mole of gas = 22.4 liters.

112 L * 1 mol/22.4 L = 5 mol CO₂

Find moles of methanol:

Based on the chemical equation, for every 2 mol methanol, there are 2 mol carbon dioxide. So for every 5 mol carbon dioxide, there are 5 mol methanol!

5 mol CO₂ = 5 mol CH₃OH

Molar mass of methanol: 12.01 + 3*1.008 + 16.00 + 1.008 = 32.04 g/mol

Moles of methanol: 5 mol * 32.04 g/mol = 160.2 g methanol

≈ 160 mol methanol

8 0

2 years ago

List the number of each type of atom on the left side of the equation C5H12(g)+8O2(g)→5CO2(g)+6H2O(g) C 5 H 12 ( g ) + 8 O 2 ( g

Gala2k [10]

Answer:

Carbon=5, hydrogen=12, oxygen=16

Explanation:

Carbon=5, hydrogen=12, oxygen=16

In order to effectively count the number of atoms, we look at the equation closely and take note of the stoichiometric coefficients of each reactant as this influences the number of atoms of that element present.

For instance, oxygen is diatomic and has a stoichiometric coefficient of 8. This implies the there are sixteen atoms of oxygen altogether.

Note that the left hand side refers to the reactants side.

5 0

2 years ago

Read 2 more answers

If 10.0 grams of NaHCO3 is added to 10.0 g of HCl, determine the efficiency of baking soda as an antacid if 6.73 g of NaCl was p

Lapatulllka [165]

Answer:

percentage yield of NaCl = 96.64%

Explanation:

The reaction was between NaHCO3 and HCl .The chemical equation can be represented below:

NaHCO3 + HCl → NaCl + H2O + CO2 . The balance equation is

NaHCO3 + HCl → NaCl + H2O + CO2

The question ask us to calculate the percentage yield of NaCl.

The efficiency of NaHCO3 as an antacid , the limiting reactant is NaHCO3

1 mole of NaHCO3 produces 1 mole of NaCl

Therefore,

molar mass of NaHCO3 = 23 +1 + 12 + 48 = 84 g

molar mass of NaCl = 23 + 35.5 = 58.5 g

1 mole of NaHCO3 = 84 g

1 mole of NaCl = 58.5 g

since 84 g of NaHCO3 produces 58.5 g of NaCl

10 g of NaHCO3 will produce ? grams of NaCl

cross multiply

Theoretical yield of NaCl = (10 × 58.5)/84

Theoretical yield of NaCl = 585/84

Theoretical yield of NaCl = 6.9642857143 g

percentage yield of NaCl = actual yield/theoretical yield × 100

percentage yield of NaCl = 6.73/6.9642857143 × 100

percentage yield of NaCl = 673/6.9642857143

percentage yield of NaCl = 96.635897436%

percentage yield of NaCl = 96.64%

3 0

2 years ago

Read 2 more answers

The specific heat of aluminum is 0.214 cal/g.oC. Determine the energy, in calories, necessary to raise the temperature of a 55.5

Natasha2012 [34]

For this problem, we use the formula for sensible heat which is written below:

Q= mCpΔT
where Q is the energy
Cp is the specific heat capacity
ΔT is the temperature difference

Q = (55.5 g)(0.214 cal/g·°C)(48.6°C- 23°C)
Q = 304.05 cal

4 0

2 years ago