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3 years ago

Explain how the cell membrane controls the movement of materials into and out of the cell ?

1 answer:

5 0

It's called simple diffusion, the small molecules without charges such as oxygen and carbon dioxide can flow through a plasma membrane without assistance and without expending energy. Other substances such as proteins, glucose and charged particles called ions cannot pass through the selectively permeable membrane.

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Find the density of a material, given that a 5.01 g sample occupies 3.46 mL

Alex73 [517]

Answer:

The answer is

Explanation:

The density of a substance can be found by using the formula

$density = \frac{mass}{volume}$

From the question

mass of material = 5.01 g

volume = 3.46 mL

The density of the material is

$density = \frac{5.01}{3.46} \\ = 1.44797687...$

We have the final answer as

Hope this helps you

3 0

3 years ago

In a chemical reaction 88g of CO2 was produced at r.t.p. <br> Calculate the volume of CO2 in dm??

Tems11 [23]

Explanation:

$RFM = 44 \: g \\ 44g \: contain \: 1 \: mole \\ 88g \: will \: contain \: ( \frac{88}{44} \times 1) \\ = 2 \: moles \\ at \: room \: temperature \\ 1 \: mole \: occupies \: 24 \: {dm}^{3} \\ 2 \: moles \: occupies \: (2 \times 24) \\ = 48 \: {dm}^{3}$

6 0

3 years ago

How does the density of a hershey bar compare to the density of the a half bar?

anastassius [24]

The density would be the same for the whole bar as well as one half of the bar. Density is a identity I believe, by this I mean that it stays the same no matter how little or how much of the same substance you have. Since density = mass / volume, half the bar has half of the weight as well as half of the volume of the whole bar, making the density the same.

For example, a block weighs 10 grams and has a volume of 5 ml. the density would be d = 10/5 or, d = 2g/ml

Half of the block weighs 5 grams and has a volume of 2.5 ml. The density is d = 5/2.5, or, d = 2 g/ml.

See, although there are different amounts of the same substance, their density is the same.

8 0

2 years ago

Liquid A and liquid B form a solution that behaves ideally according to Raoult's law. The vapor pressures of the pure substances

Rama09 [41]

Answer:

Vapor pressure of solution → 151.1 Torr

Option 2.

Explanation:

Raoult's Law is relationed to colligative property about vapor pressure. A determined solute, can make, the vapor pressure of solution decreases.

ΔP = P° . Xm

where Xm is the mole fraction of solute, P° (vapor pressure of pure solvent)

and ΔP = Vapor pressure of pure solvent - Vapor pressure of solution.

In order to determine the vapor pressure of solution, we need to determine, the vapor pressure of B and A in the solution

B's pressure = P° B . Xm

When we add A to B, A works as the solute and B, as the solvent.

Vapor pressure of pure B is 135 torr. (P° B)

In order to determine, the Xm, we use the moles of A and B

Xm = 5.3 mol of B / (1.28 + 5.3) → 0.806

B's pressure = 135 Torr . 0.806 → 108.81 Torr

If mole fraction of B is 0.806, mole fraction for A (solute) will be (1 - 0.806)

A's pressure = 218 Torr . 0.194 → 42.3 Torr

Vapor pressure of solution is sum of vapor pressures of solute + solvent.

Vapor pressure of solution = 42.3 Torr + 108.81 Torr → 151.1 Torr

6 0

3 years ago

The mass of a solid substance is 21.112 g. If the volume of the solid substance is 19.5 cm3, calculate the density of the substa

Ostrovityanka [42]

Answer:

ρ = 1.08 g/cm³

Explanation:

Step 1: Given data

Mass of the substance (m): 21.112 g

Volume of the substance (V): 19.5 cm³

Step 2: Calculate the density of the substance

The density (ρ) of a substance is equal to its mass divided by its volume.

ρ = m / V

ρ = 21.112 g / 19.5 cm³

ρ = 1.08 g/cm³

The density of the substance is 1.08 g/cm³.

6 0

3 years ago