Please help asap!!!!!!!!!!! How many molecules are present in 0.5 moles of NaOH?

The shielding of electrons gives rise to an effective nuclear charge, Zeff, which explains why boron is larger than oxygen. Esti

Vesna [10]

Zeff = Z - S

Here, Z is the number of protons in the nucleus, that is, atomic number, and S is the number of nonvalence electrons.

For boron, the electronic configuration is 1s₂ 2s₂ 2p₄

Z = 5, S = 2

Zeff = 5-2 = +3

For O, electronic configuration is 1s₂ 2s₂ 2p₄

Z = 8, S = 2

Zeff = 8-2 = +6

Hence, the correct answer is second option, that is, +3 and +6, the Zeff of boron is smaller in comparison to O, thus, boron exhibits a bigger size than O.

3 0

3 years ago

The specific heat of gold is 0.031 calories/gram°C and the specific heat of silver is 0.057 calories/gram°C. If equal amounts of

Vikki [24]

I think the substance that will heat up faster would be the silver metal since it has a higher heat capacity. Heat capacity is the amount of heat needed to raise the temperature of the system into one degree. Heat capacity and heat energy is directly related so higher value of heat capacity would lead to higher heat energy.

3 0

3 years ago

Read 2 more answers

Acetic acid, CH3COOH, can be produced by bubbling oxygen gas into acetaldehyde, CH3CHO, in the presence of

slamgirl [31]

Explanation:

The balanced equation for the reaction is given as;

2CH3CHO + O2 → 2CH3COOH

If 20.0 g CH3CHO and 10.0 g O2 were put into a reaction vessel, (a)

how many grams of acetic acid will be produced?

First thing's first, we have to find he limiting reactant. This is done by comparing the number of moles of the reactants.

From the equation of the reaction;

2 mol of CH3CHO reacts with 1 mol of O2

From the masses given;

Number of moles = Mass / Molar mass

CH3CHO;

Number of moles = 20 / 44.0526 = 0.454 mol

O2;

Number of moles = 10 / 32 = 0.3125 mol

The limiting reactant is CH3CHO because O2 would be in excess.

Back to the question;

2 mol of CH3CHO produces 2 mol of CH3COOH

0.454 mol would produce x

Solving for x;

x = 0.454 * 2 / 2 = 0.454 mol

Converting to mass;

Mass = number of moles* Molar mass

Mass = 0.454 mol * 60.052 g/mol = 27.26 grams

(b) how many grams of the excess reactant remain after the reaction is

complete

The excess reactant is O2

Number of moles left = Initial Number of moles - Number of moles that reacted

Number of moles left = 0.3125 mol - (0.454 mol / 2)

Number of moles left = 0.0855 mol

Converting to mass;

Mass = 0.0855 mol * 32 g/mol = 2.736 grams

6 0

3 years ago

What is hydrolisation

Aliun [14]

Basically taking water, and then making a different compound react with the water.

5 0

3 years ago

You have 345 mL of a 2.5 M NaCl solution. If you boil the water until the volume of the solution is 250 mLwhat will the molarity

HACTEHA [7]

The molarity of the solution will be 3.45 M

<h3>Further explanation </h3>

Dilution is the process of adding a solvent to get a more dilute solution.

The moles(n) before and after dilution are the same.

Can be formulated :

M₁V₁=M₂V₂

M₁ = Molarity of the solution before dilution

V₁ = volume of the solution before dilution

M₂ = Molarity of the solution after dilution

V₂ = Molarity volume of the solution after dilution

The initial solution

345 mL of a 2.5 M NaCl solution.

M₁=2.5 M

V₁=345 ml

The solution after boiled :

V₂=250 ml

$\tt M_2=\dfrac{M_1.V_1}{V_2}\\\\M_2=\dfrac{2.5\times 345}{250}\\\\M_2=3.45~M$

5 0

2 years ago