CHEMISTRY COLLEGE

Which statement is true about the cell membrane? It allows an unlimited amount of water to enter. It stops waste substances from passing through. It is not selective about which gases enter or leave the cell. It is selective about which substances enter or leave the cell.

Answers

Answer 1

Answer:

Answer:

It is selective about which substances enter or leave the cell.

Explanation:

Also srry for spamming u all the time.

UwU hope this helps tho

Answer 2

Answer:

Answer:

It is selective about which substances enter or leave the cell

Explanation:

I have learned this already

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A solid is hard brittle and electrically nonconducting. it's melt ( the liquid form of the substance) and an aqueous solution containing the substance conduct electricity. classify solid.

Answers

Answer: ionic solid

Explanation:

In an ionic solid, the ions are bound together by strong electrostatic attraction hence they are immobile and the solid is unable to conduct electricity. If this solid is dissolved in water, the ions move apart due to solvation and become mobile hence the solution conduts electricity. Similarly, when the solid melts, the ions also become free and the melt conduct electricity.

How many grams of NaCl are produced when 0.548 moles of Na react with excess Cl2 according to the reaction above?2Na + Cl2 --> 2NaCl

Answers

Answer:

$\boxed {\boxed {\sf 32.0 \ g \ NaCl}}$

Explanation:

To solve this problem, we must use stoichiometry: the calculation of reactants and products in a chemical reaction using ratios.

1. Analyze the Reaction

$2Na+Cl_2 \rightarrow 2 NaCl$

Check the coefficients, which indicate the moles required for the reaction. 2 moles of sodium (Na) and 1 mole of chlorine (Cl₂) produces 2 moles of sodium chloride (NaCl).

2. Set Up Ratios.

We are asked to find the grams of NaCl produced when 0.548 moles of Na react with excess chlorine.

We need 2 ratios: 1 for finding the moles of NaCl produced and 1 for converting to grams.

The first ratio is found using the coefficients. Since there is excess chlorine, we only need to focus on the sodium and sodium chloride. According to their coefficients, 2 moles of Na produce 2 moles of NaCl. This is the first ratio.

$\frac { 2 \ mol \ Na }{2 \ mol \ NaCl}$

The second ratio uses the molar mass. Since we are solving for the grams of NaCl, we have to find its molar mass.

First, locate these values on the Periodic Table for the individual elements.

Na: 22.989769 g/mol
Cl: 35.45 g/mol

There is 1 of each atom in 1 molecule, so we can add these values.

NaCl: 58.439769 g/mol

Use this value as the second ratio.

$\frac {58.439769 \ g \ NaCl}{1 \ mol \ NaCl}$

3. Calculate

Make 1 expression using the 2 ratios and the initial value of moles.

$0.548 \ mol \ Na * \frac { 2 \ mol \ Na }{2 \ mol \ NaCl} * \frac {58.439769 \ g \ NaCl}{1 \ mol \ NaCl}$

Flip the ratios so the correct units cancel out.

$0.548 \ mol \ Na * \frac { 2 \ mol \ NaCl }{2 \ mol \ Na} * \frac {58.439769 \ g \ NaCl}{1 \ mol \ NaCl}$

Multiply. Note that the moles of Na (units) cancel and the moles of NaCl (units). cancel.

$0.548 * \frac { 2 }{2 } * \frac {58.439769 \ g \ NaCl}{1}$

$\frac {0.548 *2* 58.439769 \ g \ NaCl}{2}$

$\frac {64.049986824 \ g \ NaCl}{2} =32.024993412 \ g\ NaCl$

The original value of moles has 3 significant figures, so our answer must have the same. For the number we found, that is the tenth place.

32.02499341232

The 2 in the hundredth place tells us to leave the 0.

$32.0 \ g \ NaCl$

0.548 moles of sodium react with excess chlorine to produce 32.0 grams of sodium chloride.

7. What is the molar mass of each of the following elements?a) helium, He(s)
c) potassium, K(s)
b) manganese, Mn(s)
d) boron, B(s)

Answers

Answer:

The molar mass of:

Helium = 4.00 g/mol

Potassium = 39.0983 g/mol

Manganese = 54.94 g/mol.

Boron = 10.81 g / mol

Explanation:

Helium = 4.00 g/mol

Potassium = 39.0983 g/mol

Manganese = 54.94 g/mol.

Boron = 10.81 g / mol

Briefly explain why sublimation occurs.

Answers

Answer:

Sublimation is basically cause by the heat absorption and this process is an endothermic since it require extra energy.

It basically provide sufficient energy to molecules to control the various type of attractive forces from the neighbors and then convert it into the vapor phase.

Sublimation occur when the particle of gases become cold because some substances has high vapor pressure. Sublimation is the endothermic change and it occur below the triple point in terms of pressure and temperature.

A mixture of neon and xenon gases, at a total pressure of 739 mm Hg, contains 0.919 grams of neon and 19.1 grams of xenon. What is the partial pressure of each gas in the mixture?_______g Xe

Answers

Answer:

Partial pressure of neon = 175 mmHg

Partial pressure of xenon = 564 mmHg

Explanation:

The partial pressure of a gas in a mixture can be calculated as the product of the mole fraction of the gas (Xi) and the total pressure (Pt), as follows:

Pi = Xi Pt

The total pressure is 739 mmHg ⇒ Pt = 739 mmHg

In order to calculate the mole fraction of each gas, we have to first calculate the number of moles of each gas (n) by dividing the mass of the gas into the molar mass (MM):

For neon gas (Ne):

MM(Ne) = 20.18 g/mol

n(Ne)= mass/MM = 0.919 g x 1 mol/20.18 g = 0.045 mol Ne

For xenon gas (Xe):

MM(Xe) = 131.3 g/mol

n(Xe)= mass/MM = 19.1 g x 1 mol/131.3 g = 0.145 mol Xe

Now, we calculate the mole fraction (X) by dividing the number of moles of the gas into the total number of moles (nt):

nt= moles Ne + moles Xe = 0.045 mol + 0.145 mol = 0.190 mol

X(Ne) = moles Ne/nt = 0.045 mol/0.190 mol = 0.237

X(Xe) = moles Xe/nt = 0.145/0.190 mol = 0.763

Finally, we calculate the partial pressures of Ne and Xe as follows:

P(Ne) = X(Ne) x Pt = 0.237 x 739 mmHg = 175 mmHg