Elements in the 2nd family/group gain or lose electrons? *

In 1773 Benjamin Franklin, investigating the calming effect of oil on the water of a pond near London, observed that a teaspoonf

likoan [24]

Answer:

a. 2.44 nm

b. 15.33 nm²

Explanation:

a. Calculate the thickness (in nm) of the surface film

Since the volume of a teaspoon equals V = 4.93 cm³ and the area of the oil film is half an acre = 1/2 × 4046.86 m² = 2023.43 m²

The volume of the oil film, V' equals the volume of the oil in the teaspoon, V

V' = Ah where A = cross-sectional area of oil film = 2023.43 m² = 2023.43 × 10⁴ cm² and h = height of oil film

So, V' = V

Ah = V

h = V/A

= 4.93 cm³/2023.43 × 10⁴ cm²

= 0.00244 × 10⁻⁴ cm

= 2.44 × 10⁻⁷ cm

= 2.44 × 10⁻⁷ cm × 1m/100 cm

= 2.44 × 10⁻⁹ m

= 2.44 nm

b. The surface area (in nm2) occupied by an oleic acid molecule on water.

Since the height of the oil film equals the diameter of the oil molecule, and the molecule is assumed to be a sphere of radius, r. Its surface area is thus A = 4πr²

r = h/2 = 2.44 nm/2 = 1.22 nm

A = 4πr²

A = 4π(1.22 nm)²

A = 4.88π nm²

A = 15.33 nm²

7 0

3 years ago

Hydrogen cyanide is used to prepare sodium cyanide, which is used in part to obtain gold from gold-containing rock. If a reac- t

Sliva [168]

Answer:

Mass of HCN produced = 6.75 g

Explanation:

Reaction is as follows:

$2NH_3+3O_2+2CH_4 \rightarrow 2HCN + 6H_2O$

First calculate the no. of moles of each chemical species.

molecular mass of $NH_3$ is 17 g/mol

No. of mol of $NH_3$ = 11.5/17 = 0.676 mol

Molecular mass of $O_2$ = 32 g/mol

No. of mol of $O_2$ = 12/32 = 0.375

Molecular mass of $CH_4$ = 16 g/mol

No. of mol of $CH_4$ = 10.5/16 = 0.656 mol

from the balanced chemical reaction, it is clear that 2-moles ammonia reacts with 3 moles oxygen and 2 moles methane to form 2 moles of HCN.

or, 1-mol ammonia reacts with 1.5 mol oxygen and 1 mol methane to form 1 mol of HCN.

Thus, no. of oxygen present is less than required and so it will act as limiting reagent.

From the chemical equation,

3 moles oxygen produces 2 moles HCN

or one mole oxygen produces (2/3) moles HCN

0.375 moles oxygen produces (2/3) × 0.375 HCN = 0.25 moles of HCN

molar mass of HCN = 27 g/mole

Mass = mol × molar mass

mass of HCN = 27 × 0.25 = 6.75 g

8 0

3 years ago

How would you increase the amount of garbage that is recycled at your school

melamori03 [73]

Make sure you have recycling bens in classrooms and in hallways. remind the teachers to keep on the students so they will get in the habit to recycle. This could reduce garbage and increase recycling! hope it works for you! :)

3 0

3 years ago

Please help! 30 points!

lisabon 2012 [21]

The person above me is correct

8 0

3 years ago

If you were an astrobiologist, what would you do to search for life?

Bess [88]

Astrobiologist means someone who studies the possibilities of life beyond earth. what would YOU do to search for life? They're asking for your opinion :)

3 0

2 years ago