What is the answer to 10?

Choose the pure substance from the list below. choose the pure substance from the list below. lemonade wine air juice salt

vfiekz [6]

I believe the answer is salt. because it is a compound of two distinct elements that can be broken down without changing the properties of substance.
A pure substance is a substance that are made up of only one type of an atom or one type of a molecule. Pure substances may be further broken down into elements and compounds.

3 0

3 years ago

How much does one mole of carbon weigh (round to two decimal places)? Make sure your answer has units.

IgorC [24]

The number of atoms present in carbon, specifically Carbon-12, is the number of atoms present in 1 gram of the substance. One moles of the substance weighs approximately 12.01 g/mole. The unit suggests that every mole of carbon weighs 12.01 grams.

4 0

2 years ago

The density of helium is 0.17 g/L. What Is the mass of helium in a 5.4 L helium balloon? (2 sig figs) *

ioda

Answer:

The correct answer is 0.92 g

Explanation:

The density is defined as the mass per unit of volume:

Density= mass/volume

From the data provided:

volume= 5.4 L

density= 0.17 g/L

Thus, to calculate the mass of helium:

mass= density x volume = 0.17 g/L x 5.4 L= 0.918 g ≅ 0.92 g

6 0

3 years ago

The effective nuclear charge is the amount of charge experienced by an electron taking into account any shielding effects from o

Agata [3.3K]

Answer:

The nuclear charge increases from boron to carbon, but there is no additional shielding( that is no additional shells).

Explanation:

First of all, we must know the electron configuration of carbon and boron.

Boron- 1s2 2s2 2p1

Carbon- 1s2 2s2 2p2

Moving from boron to carbon, the effective nuclear charge increases without a corresponding increase in the number of shells. Remember that shielding increases with increase in the number of intervening shells between the outermost electron and the nucleus. Since there isn't an increase in shells, boron experience a lower screening effect.

From

Zeff= Z- S

The Z for carbon is 6 while for boron is 5 even though both have the same number of screening electron S(4 screening electrons). Hence it is expected the Zeff(effective nuclear charge) for boron will be less than that of carbon.

6 0

3 years ago

Calculate the concentrations of all species present in a 0.26 M solution of ethylammonium chloride (C2H5NH3Cl).

Alina [70]

Answer:

0.00000223

Explanation:

pKa for C2H5NH3+ = 10.7

pKw = 14.0

pKa + pKb = pKw

10.7 + pKb = 14.0

pKb = 14.0 - 10.7

pKb = 3.30

C2H5NH3Cl is a salt of ethylamine and HCl so it will dissolve in water to produce C2H5NH3^+ + Cl^-

The base hydrolysis reaction: C2H5NH3^+(aq) + H2O(l) <=> C2H5NH2(aq) + H3O^+(aq)

This reaction is described by Kb.

Kb = [C2H5NH2][H3O^+]/[C2H5NH3^+]

Let [C2H5NH2] = [H3O^+] = x,

so [C2H5NH3^+] = 0.26 - x

Kb = x^2/(0.26 - x) = 2.00 x 10^-11

Let's solve for x. In this equation, It is possible to solve without the use quadratic equation. So we can assume that 0.26 - x is approximately equal to 0.26. We won't know until we do the calculation.

We get: x^2 + 2.00 x 10^-11x - 4.99 x 10^-12 = 0

With the use of a quadratic calculator.

x = 2.23 x 10^-6 M = [C2H5NH2] = [H3O^+]

0.26 - x is just 0.26 M in this problem because 2.23 x 10^-6 M is insignificant.

[C2H5NH3^+] = 0.26 M = [Cl^-]

NOTE:

pH = -log [H3O^+] = -log(2.23 x 10^-6) = 5.65

Ka is the acid dissociation constant

Kb is the base dissociation constant

5 0

3 years ago