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A toothpaste contains 0.254 % by mass sodium fluoride used to prevent dental caries and 4.4 % by mass KNO3, which decreases pain sensitivity. One tube contains 119 g of toothpaste.

Part A
How many moles of NaF are in the tube of toothpaste?
Express your answer using three significant figures.
Part B
How many fluoride ions, F−, are in the tube of toothpaste?
Express your answer using three significant figures.
Part C
How many grams of sodium ion, Na+, are in 1.35 g of toothpaste?
Express your answer using three significant figures.
Part D
How many KNO3 formula units are in the tube of toothpaste?
Express your answer using two significant figures.
Part E
What is the molar mass of ammonium sulfate?
Express your answer using four significant figures.

Part F

Chloroform, CHCl3, was formerly used as an anesthetic but its use was discontinued due to respiratory and cardiac failure.

How many grams are in 0.133 moles of chloroform?

How many moles are in 35.0 g of chloroform?

Respuesta :

jufsanabriasa

Answer:

A. 7,20x10⁻³mol NaF

B. 4,33x10²¹ F⁻ ions

C. 1,88x10⁻³g Na⁺

D. 3,1x10²² formula units

E. 132,08g/mol

F. 15,9g of CHCl₃; 0,293 mol of CHCl₃

Explanation:

A. 119g × (0,254% / 100) = 0,302g of NaF × (1mol / 41,99g) = 7,20x10⁻³mol NaF

B. 7,20x10⁻³mol NaF ≡ 7,20x10⁻³mol F⁻ × (6,022x10²³ ions / mol) = 4,33x10²¹ F⁻ ions

C. 1,35g × (0,254% / 100) = 0,00343g of NaF × (22,99g Na⁺ / 41,99g NaF) = 1,88x10⁻³g Na⁺

D. 119g × (4,4% / 100) = 5,236g of KNO₃ × (1mol / 101,1g) = 0,0518mol × (6,022x10²³ F.U / 1mol) = 3,1x10²² formula units

E. Formula of ammonium sulfate is (NH₄)₂SO₄. Molar mass is obtained thus:

N: 2N×(14g/mol) = 28g/mol

H: 8H×(1,01g/mol) = 8,08g/mol

S: 1S×(32g/mol) = 32g/mol

O: 4O×(16g/mol) = 64g/mol

Molar mass: 28 + 8,08 + 32 + 64 = 132,08g/mol

F. Molar mass of chloroform is 119,38g/mol, thus:

0,133 mol × (119,38g/mol) = 15,9g of CHCl₃

35,0g  × (1mol / 119,38g) = 0,293mol of CHCl₃

I hope it helps!

mickymike92

The moles and number of particles in each of the given compounds are determines from the given mass and the molar masses of the compounds.

How can moles of a substance be determined?

Moles of a substance is determined using the formula below:

  • Moles = mass ÷ molar mass

A. Molar mass of NaF = 42.0 g/mol

Moles of NaF in the tube of toothpaste is:

119g × 0.254% ÷ 42 g/mol = 7.20x10⁻³mol NaF

B. 7.20 × 10⁻³mol NaF produces 7.20x10⁻³mol F⁻

Number of fluoride ions = 7.20x10⁻³mol F⁻ × 6.022x10²³ = 4.33x10²¹ F⁻ ions

C. Grams of sodium ions in 1.35 g of toothpaste is determined as follows:

1.35g × 0.254% × 23.0g Na⁺ / 42 g NaF) = 1.88x10⁻³g Na⁺

D. Molar mass of KNO₃ = 101.1 g/mol

Formula units of KNO₃ in the tube of toothpaste is:

119g × 4.4% ÷ 101.1g × 6.022x10²³ F.U / 1mol = 3.1 x10²² formula units of KNO₃

E. Molar mass of ammonium sulfate (NH₄)₂SO₄ is 132.08g/mol

F. Molar mass of chloroform = 119.38g/mol

Grams of chloroform in 0.33 moles is:

0.33 mol × 119.38g/mol = 15.9g of CHCl₃

Moles of chloroform in 35.0 g is:

35,0g  ÷ 119.38g = 0.293 moles of CHCl₃

Therefore, the moles and number of particles in each of the given compounds are determines from the given mass and the molar masses of the compounds.

Learn more about molar mass and moles at: https://brainly.com/question/837939

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