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3 years ago

Describe how phospholipids form a barrier between water inside the cell and water outside the cell

1 answer:

6 0

Phospholipids would have to form a phospholipid bilayer in order to achieve water on the outside and water inside. This is because the nonpolar tails of the phospholipids are facing each other in a water environment because they cannot interact with the water, only their own tails, while the phosphate heads of the molecule face the periphery of the tails and interact with water. Micelles are the simplest examples of these.

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A chemist weighed out 20.7 g of sodium . Calculate the number of moles of sodium she weighed out

Pachacha [2.7K]

Answer:

about 0.9 mol

Explanation:

there are 22.990 g/mol of Na

20.7/22.99 = 0.900391 mol

about 0.9 mol

8 0

4 years ago

calculate the volume occupied by 10g of propane gas, under normal conditions of temperature and pressure

andriy [413]

Answer:

5.5 L

Explanation:

First we convert 10 g of propane gas (C₃H₈) to moles, using its molar mass:

10 g ÷ 44 g/mol = 0.23 mol

Then we use the PV=nRT formula, where:

P = 1 atm & T = 293 K (This are normal conditions of T and P)

n = 0.23 mol

R = 0.082 atm·L·mol⁻¹·K⁻¹

V = ?

1 atm * V = 0.23 mol * 0.082 atm·L·mol⁻¹·K⁻¹ * 293 K

V = 5.5 L

3 0

3 years ago

PLEASE HELP ME!!! ASAP

shtirl [24]

Answer:

Theoretical yield of the reaction = 34 g

Excess reactant is hydrogen

Limiting reactant is nitrogen

Explanation:

Given there is 100 g of nitrogen and 100 g of hydrogen

Number of moles of nitrogen = 100 ÷ 28 = 3·57

Number of moles of hydrogen = 100 ÷ 2 = 50

Reaction between nitrogen and hydrogen yields ammonia according to the following chemical equation

N2 + 3H2 → 2NH3

From the above chemical equation for every mole of nitrogen that reacts, 3 moles of hydrogen will be required and 2 moles of ammonia will be formed

Now we have 3·57 moles of nitrogen and therefore we require 3 × 3·57 moles of hydrogen

⇒ We require 10·71 moles of hydrogen

But we have 50 moles of hydrogen

∴ Limiting reactant is nitrogen and excess reactant is hydrogen

From the balanced chemical equation the yield will be 2 × 3·57 moles of ammonia

Molecular weight of ammonia = 17 g

∴ Theoretical yield of the reaction = 2 × 3·57 × 17 = 121·38 g

5 0

4 years ago

What is the new concentration of a solution of CaSO3 if 10.0 mL of a 2.0 M CaSO3 solution is diluted to 100 ml?

kifflom [539]

Answer: The new concentration of a solution of $CaSO_{3}$ is 0.2 M 10.0 mL of a 2.0 M $CaSO_{3}$ solution is diluted to 100 mL.

Explanation:

Given: $V_{1}$ = 10.0 mL, $M_{1}$ = 2.0 M

$V_{2}$ = 100 mL, $M_{2}$ = ?

Formula used to calculate the new concentration is as follows.

$M_{1}V_{1} = M_{2}V_{2}$

Substitute the values into above formula as follows.

$M_{1}V_{1} = M_{2}V_{2}\\10.0 mL \times 2.0 M = M_{2} \times 100 mL\\M_{2} = 0.2 M$

Thus, we can conclude that the new concentration of a solution of $CaSO_{3}$ is 0.2 M 10.0 mL of a 2.0 M $CaSO_{3}$ solution is diluted to 100 mL.

5 0

3 years ago

The hydrochloride form of cocaine has a solubility of 1.00 g in 0.400 mL water. Calculate the molarity of a saturated solution o

Tanya [424]

Answer:

The molarity of the solution is 7.4 mol/L

Explanation:

From the question above

0.400 ml of water contains 1.00 g of hydrochloride form of cocaine

Therefore 1000 ml of water will contain x g of hydrochloride form of cocaine

x = 1000 / 0.400

x = 2500 g

2500g of hydrochloride form of cocaine is present in 1000 ml of water.

Mole of hydrochloride form of cocaine = mass /molar mass of hydrochloride

Mole of hydrochloride form of cocaine = 2500/339.8

= 7.4 mol

Molarity = mol/ volume in liter (L)

molarity = 7.4 /1

Molarity = 7.4 mol/L

6 0

3 years ago

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