Which of the following properties of an unknown substance would allow it to be classified as a mixture? The unknown substance
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Answer:

[H₂A] = 0.2M

[HA⁻] = 0.8M

Explanation:

A compound with 2 ionizable groups has as equilbriums:

H₂A ⇄ HA⁻ + H⁺ ⇄ A²⁻ + H⁺

A pH of 6.8 is near to the first equilibrium:

H₂A ⇄ HA⁻ + H pKa = 6.2

To determine concentrations of the acid H₂A and conjugate base HA⁻ we use H-H equation:

pH = pKA + log [HA⁻] / [H₂A]

6.8 = 6.2 + log [HA⁻] / [H₂A]

0.6 = log [HA⁻] / [H₂A]

3.981 = [HA⁻] / [H₂A] (1)

As concentration of the buffer is 1.0M:

1M = [HA⁻] + [H₂A] (2)

Replacing (2) in (1):

3.981 = 1- [H₂A] / [H₂A]

3.981[H₂A] = 1 - [H₂A]

4.981 [H₂A] = 1

[H₂A] = 0.2M

And [HA] = 1M - 0.2M = 0.8M

Answer:

It's a list of metals from most to least reactive.

Explanation:

You should be able to find it listed really easily online.

Answer:

Periods are horizontal rows while the groups are the vertical columns on the periodic table.

Answer Scientist

Explanation:

Answer:

sulfur

Explanation:

protons: 16 neutrons: 16 electrons: 2,8,6 i hope this helps!

Answer:

b

Explanation:

Answer:

False

Explanation:

Molecules of the same substance are made up of the same type of atoms and look exactly alike.

Hence, if I have two molecules of methane having exactly the same atoms of carbon and hydrogen,the both are indistinguishable from each other based on appearance.

Hence all molecules of methane are exactly alike if they are composed of atoms of the same isotope of hydrogen and carbon.

Answer:

Explanation:

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

[tex]Density = \frac{mass}{volume} [/tex]

Since we are finding the mass

From the question

Density = 0.81 g/mL

volume = 247.2 mL

Substitute the values into the above formula and solve for the mass

mass = 0.81 × 247.2

= 200.232

We have the final answer as

Hope this helps you

Answer:

4 sig figs.

Explanation:

Significant Figures Rules:

1. Anything that isn't a zero is a sig fig

2. If a decimal point comes after the ones digit, everything before the decimal is counted as sig fig (i.e 2000. would be 4 sig figs).

3. If we are dealing with small decimals, the zero before and after the decimal (i.e 0.002) is a placeholder and is not counted as sig figs.

4. Any zeros between 2 significant digits is considered in sig figs (i.e 2002 would be 4 sig figs).

We look at 0.001022.

We know that 0.00 are not sig figs and are placeholders.

We know that 1022 are significant digits and figures, and we have 4 of them.

Therefore, we have 4 sig figs.

My answer to the question is 4 significant figures.

Answer:

A: Control Group

Explanation:

The control group is part of an expierment left untouched by anything that could possibly alter it, in the case of this question, the students have two groups of plants that have drops of liquid that could alter them, in order to see the growth, and to see if the liquid actually did anything, in order to do so, you would have to have a untouched plant, that shows what it looks like with out any alteration from researchers. So the answer would be control group.

Answer:

i think control group?

Explanation:

meow x3 UwU

Answer:

2.7005 g/cm²

explanation: as we know density=mass/volume

Answer:

A 3s orbital is at a greater average distance from the nucleus than a 2s orbital

Explanation:

As the principal quantum number n increases, the distance of the orbital from the nucleus increases. Hence if we consider the 2s and 3s orbitals, it is easy to see that the 3s orbital is at a greater distance from the nucleus than the 2s orbitals.

This is clearly seen when we plot the radial distribution against the distance from the nucleus. This enables us to visualize the region in space in which an electron may be found.

Answer:

A and C

Explanation:

A; Animals inhale and exhale, breath oxygen, leave carbon dioxide.

C; We fart, so do they! (farts are a release of methane gas from our bodies) Just ask my dog...

Hope this helped!

The molecule(s) in the atmosphere that comes from animals is -

Humans and other animals contribute to the atmospheric gas cycle such as nitrogen gas, oxygen gas, carbon dioxide, and other gases. Animals give up mainly two gases in the atmosphere that are:

Thus, the molecule(s) in the atmosphere that comes from animals is -

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Answer:

Explanation:

Dmitri Mendeleev developed a chart-like arrangement of the elements called the Periodic Table ______ . He stated that if the elements were listed in order of increasing atomic mass______, their properties repeated in a regular manner. He called this the periodicity of properties ______ of the elements. The arrangement used today differs from that of Mendeleev in that the elements are arranged in order of increasing atomic number______. Each horizontal row of elements is called a(n)period ______. Each vertical column is called a(n) column_____, or , because of the resemblance between elements in the same column, a(n) __group____.

1. Dmitri Mendeleev developed a chart-like arrangement of the chemical elements called the: periodic table.

2. According to Dmitri Mendeleev, the properties of chemical elements are repeated in a regular manner, if the chemical elements were listed in order of increasing: atomic mass.

3. Dmitri Mendeleev called the increasing order of chemical elements on the periodic table: the Periodic Law of the elements.

4. The arrangement used today differs from that of Dmitri Mendeleev in that the chemical elements are arranged in order of increasing: atomic number.

5. Each horizontal row of chemical elements is called a: period.

6. Each vertical column is of chemical elements is called a: group.

7. Because of the resemblance between chemical elements in the same column, each vertical column is called a: family.

Dmitri Ivanovich Mendeleev was a Russian chemist and inventor who was born on the 8th of February, 1834 in Tobolsk, Russia.

He formulated the Periodic Law and devised the periodic table of chemical elements.

On a periodic table, each horizontal row of chemical elements is called a period while each vertical column is of chemical elements is called a group.

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Answer:

He is probably studying Geomorphology.

Explanation:

Geology is the science that studies the composition, structure, dynamics, and history of planet Earth, the processes by which it has evolved including everything that has to do with its natural resources and with this the processes that affect the surface, and therefore, the environment.

Geomorphology is a branch of geosciences, more specifically geography and geology. One of his most interesting models explains the ways in which the earth's surface is the result of a consistent dynamic balance.

Answer:

I needed to use good precision in my measurement for my chemistry lab

Explanation:

Answer:

Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form.

Explanation:

i took the test:P

Hope this helps!

Answer:

Explanation:

All it takes is a momentary lapse in concentration. When you are in the laboratory and take a direct sniff of the chemicals you are using, you run the risk of damaging your mucous membranes or your lungs.

Answer:

32.23 to 4 significant figures.

Explanation:

The molar mass of the element is the mass of 6.022 * 10^23 atoms (Avogadro's number).

So by proportion it is 6.022 * 10^23 * 3.88 / 7.25 * 10^22

= 32.23 to 4 significant figures.

Answer:

Answer is C. Electron cloud

Explanation:

<3

Answer: The correct answer is B. It’s particles are evenly distributed. (:

Explanation:

Answer:

b

Explanation:

Answer:

3.

Explanation:

There are four nitrogenous bases in a DNA including guanine (G), adenine (A), cytosine (C) and Thymine (T) and together they form the nitrogenous base sequence arranged in a specific order of three letters such as GAC and TAG to form a genetic code.

These nitrogenous base sequences forming genetic code are amino acid specific and determine the amino acid sequence in DNA. for example: CTT determines leucine and GTT determines valine.

Hence, the correct option is "3".

Answer:

Greater

Explanation:

Answer:

a.) Its compounds can only be chemically separated into the elements that make it up.

The compound of water can only be chemically separated into the elements that make it up. The correct option is A.

A compound is made up of atoms from different elements that have been chemically combined in a specific ratio.

A mixture is a combination of two or more substances in which no chemical reaction or combination occurs. Compounds are made up of different elements arranged in a specific order via chemical bonds.

Atoms/molecules are (chemically physically) combined in a compound so that the elements that comprise the compound (retain/lose) their identities and take on a new set of properties.

The most common chemical methods of isolation and purification are distillation, crystallization, adsorption, membrane procedures, absorption and stripping, and oxidation.

Because each water molecule is made up of two hydrogen atoms and one oxygen atom, water can only be decomposed chemically.

Thus, the correct option is A.

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Answer:

The number of hydrogen atoms in 36.04 g  sample of steam is 2.408 × 10²⁴ atoms of hydrogen

Explanation:

The  given parameters are;

The mass of the sample of water, H₂O = 36.04 g

From the principle of conservation of matter, the mass of the water = The mass of the steam, therefore;

The mass of the steam = 36.04 g

The molar mass of H₂O = 18.01528 g/mol

Therefore, the number of moles, n, of H₂O in the 36.04 g of steam is given as follows;

n = Mass/(Molar Mass) = (36.04 g)/(18.01528 g/mol) = 2.00052399963 ≈ 2 moles

The number of molecules of H₂O per mole of H₂O is geven by the Avogadro's number = 6.02 × 10²³ molecules

Therefore;

The number of H₂O in 2 moles of H₂O = 2 × 6.02 × 10²³ = 1.204 × 10²⁴ molecules

The number of hydrogen atoms per molecule of H₂O = 2 hydrogen atoms

Therefore;

The number of hydrogen atoms in the 1.204 × 10²⁴ molecules of H₂O = 2 × 1.204 × 10²⁴ molecules of H₂O

Which gives;

The number of hydrogen atoms in the 1.204 × 10²⁴ molecules of H₂O = 2.408 × 10²⁴ atoms of hydrogen

Therefore;

The number of hydrogen atoms in 36.04 g  sample of steam = 2.408 × 10²⁴ atoms of hydrogen.