is helium gas a mixture or pure substance

Answers

Answer 1
An element is a pure substance as well, because if we fill up a balloon with just helium gas, it will only contain helium atoms. On the periodic table of elements, helium is element number 2 , and so that should tell you that it's an element of course.

Related Questions

Identity which statement is true:
A. Isotopes of the same element have the same atomic number and mass number, but a different
number of neutrons.
B. Isotopes of the same element have the same mass number and different atomic numbers.
C. Isotopes of the same element have the same atomic number and different mass numbers.
D. Isotopes of the same element have the same number of neutrons and a different number of protons.

Answers

ans :C
same proton(atomic no.) and electron, diff neutrons
mass no= electrons + neutrons


Isotopes of the same element have the same atomic number and different mass numbers. Hence, option C is correct.

What are Isotopes?

Isotopes are defined as chemical species which have the same number of protons but differ in the number of neutrons.

It can also be said that they are the chemical species of the same element which have the same atomic number but have different mass numbers.

For Example, C12 and C14 are the isotopes of carbon elements, which have the same atomic number but a different mass numbers.

Hence, option C is correct.

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Question 1
10 pts
A student fills a graduated cylinder with water to a volume of 22.4mL. After adding a
metal sample, the volume of the water rises to 26.2 mL. What is the volume of the
metal sample?
3.8 ml
0 22.4 mL
0 26.2 mL
O 48.6 mL

Answers

Answer:

3.8

Explanation:

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

Answers

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.

The Periodic Law of chemical elements stated that the properties of all chemical elements are repeated in a regular manner, provided the chemical elements were arranged (listed) in order of increasing atomic mass.

However, the modern periodic table of chemical elements differ because the chemical elements are arranged in order of increasing atomic number.

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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Which of the following properly describes the movement of atoms as they represent the states of matter? Atoms making liquids have less attraction than solids, but more than gases Atoms making liquids have less attraction than solids, but more than gases The atoms making liquids are closer together than atoms making solids. The atoms making liquids are closer together than atoms making solids. The atoms that make solids do not move at all which is why they keep their shape. The atoms that make solids do not move at all which is why they keep their shape. Atoms making gases have the least amount of kinetic energy while solids have the most.

Answers

Answer:

Atoms making liquids have less attraction than solids, but more than gases

Explanation:

The attraction between atoms in different molecules in a solid is very strong due to strong intermolecular forces present in a solid. However, such intermolecular forces are weaker in liquids than in solids.

This implies that the solid has higher intermolecular forces of attraction compared to gases and liquids. Based on the negligible degree of intermolecular forces between them, a gas has the weakest intermolecular forces hence the atom has very minimal interaction between them.

What gives the color and shape characteristics to flames in a fire?

Answers

Answer:

Different ions of different elements (usually metals) make a flame burn with a characteristic color when introduced into the reaction zone; the different colors are caused by the different quantized energy levels of the electrons in the different atoms.

Suppose that 7.25 x 10^22 atoms of a hypothetical element have a mass of 3.88 g. What would be the molar mass (g/mol) of this element ? Correct number of sig figs are required.

Answers

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.

7. How many significant figures are in the following numbers?
a. 0.0120350
b. 10.020
c. 12
d. 3.40 x 103

Answers

There are
A. 6 significant figures
B.5 sig figs
C.2 sig figs
D.5 sig figs

how do groups and periods on the periodic table differ??

Answers

Answer:

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

An experiment looking at structures smaller than a cell would most likely employ a

Answers

Answer Scientist

Explanation:

Please help me fast, i don't understand it.

Answers

What you are doing is correct just continue counting each hydrogen atom
Basically you have to find how many Hydrogen atoms are in the compound. The number in the corner should tell you.

C18H36O10 would be 36.
C4H10 would be 10.
NH3 would be 3.
NaHCO3 would be 1.
C6H12O6 would be 12.
H2 would be 2.

Water is a pure substance. Which of the following is true about water? (5 points)
a.) Its compounds can only be chemically separated into the elements that make it up.
b.)Its compounds can only be physically separated into the elements that make it up.
c.)It is made up of a variety of compounds, each with a different set of properties.
D.) it is made up of one element and one compound, each with the same properties.

Answers

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.

What is a compound?

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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What is the maximum number of covalent bonds that an oxygen atom with atomic number 8 can make with hydrogen?

Answers

Answer:

2

Explanation:

Oxygen has 6 electrons in its valence shell.  Since an atom can have a maximum of 8 electrons in the valence shell, oxygen has 2 empty spots in its valence.  This means that oxygen can make 2 single covalent bonds.

The maximum number of covalent bonds that an oxygen atom with atomic number 8 can make with hydrogen is: 2.

Valency can be defined as a measure of the combining power of a chemical element with other atoms to form a molecule or chemical compound.  Typically, valency is measured by the amount of hydrogen atoms that a chemical element can combine with or displace to form a molecule or chemical compound.

Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others.

From the periodic table, we know that an oxygen atom has an atomic number of eight (8). Thus, oxygen has six (6) electrons in its valence shell and two (2) empty shells to form a covalent bond with hydrogen.  

Generally, the maximum number of electrons an atom can hold in its valence shell is eight (8) and since oxygen has has six (6) electrons in its valence shell; it ultimately implies that the maximum number of covalent bonds that an oxygen atom with atomic number of eight (8) can make with hydrogen is two (2) covalent bonds.

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Students are experimenting with a substance that they
think can be added to soil to increase the number of
flowers a certain plant will make. They set up 20 pots of
soil, each planted with the same type of seed. They
divide the pots into two groups and add 15 drops of the
substance to pots in one group and only 10 drops to pots
in the other group. After the plants grow for four weeks,
the students count how many flowers each plant has
made
What does this experimental investigation lack?
a control group
an independent variable
a dependent variable
a procedure

Answers

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

True or False: PERIODS on the periodic table run up and down.

Answers

Answer:

True

Explanation:

I guessed XD But I also used Google and that's what I got

The answer is true PERIODS on the periodic table run up and down

wafting the air above a chemical is one way to it directly

Answers

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.

Question 6
1 pts
A scientist is studying a homogeneous solid with a consistent and ordered arrangement in
the lab. Which specialty is the scientist most likely working in?

Answers

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.

what is reactivity siries of metal?? ​

Answers

Answer:

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

Explanation:

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

Which is the best practice recommended in the safety video to mix and acid or a base with a solvent?

Answers

Answer:

Never pour water into acid but acid into water

Explanation:

If water is poured into extremely concentrated acid/bases, the rate of volatility and exothermic reaction is too rapid and might cause a chemical eruption, leading to acid burns.

Safety precautions hence dictate the reverse is practiced.

I believe this is a clear answer.

If the size, mass, and arrangement of atoms affect the density of a substance. How might these factors work together to cause a substance to have a low density?

Answers

Answer:  The size, mass, and arrangement of atoms affect the density of a substance. How might these factors work together to cause a substance to have a high density? A substance with smaller more massive atoms that are close together is going to have a higher density.

Explanation:

Which statement best describes chemical properties of matter?

Answers

There is not enough information for this to be answered

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!

Oleophilic materials would not be used for ?

Answers

Answer:

An oleophilic material is an entity which exhibits a higher affinity for oil than other solvents. The non-polar nature and ability to form cluster-like structures called micelles are the characteristic properties of oleophilic materials.

plz give brainlist

hope this helped you

What is chemistry? How is it used in your everyday life? Give at least two examples and explain your answers. Must have at least 4 sentences to get full credit.

Answers

Chemistry is used in our everyday life such as taking pills for a headache or baking a cake. If you were to take too many pills when you’re trying to cure a headache if could be fatal. And when baking a cake you could add to much of something and it would turn out horrible. Bc of chemistry we are able to avoid those situations in our day to day lives.

i need help with these three

Answers

hypothesis, conclusion

What is the relationship between the sequence of DNA’s subcomponents and the properties of DNA? 1. The amino acid sequence along a segment of DNA determines the three-dimensional shape of the protein that will be produced. 2. The deoxyribose sequence in a DNA molecule determines the complementary molecule that will form double stranded DNA. 3. The nitrogenous base sequence along a segment of DNA determines the amino acid sequence that will be produced. 4. The sequence of enzymes in a DNA molecule determines the direction in which DNA will be transcribed into mRNA.

Answers

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".

how many significant figures are in the number 0.001022?

Answers

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.

HELP ASAP PLEASE
Use the word Precision in a sentence relating to chemistry!

Answers

Answer:

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

Explanation:

What is the correct representation of 702.0 g in scientific notation?
A. 7.02 x 103g
B. 70.20 x 101 g
C. 7.020 x 102 g
D. 70.20 x 102 g
(answer fast !!)

Answers

Answer:

C. 7.020 x 10^2 g

Explanation:

To convert to scientific notation, move the decimal until there is only one digit greater than 1 and less than 10 before the decimal. In this case, the 7. (Depending on the conversion, you will either move the decimal to the left or right. In this question, you will need to move it left. When you move the decimal left, you inherently think you are moving it in the negative direction, but your final answer will be a positive exponent. The opposite is true for movement in the right direction, leaving a negative exponent in your final answer.)

Then, count the number of places that you moved the decimal from the original number (in this case, you moved it 2 decimal places to the left).

Because you moved the decimal 2 places to the left (-), when you write it in scientific notation, you want to annotate the exponent as the opposite, (+), so that you do not lose the equivalence of the original number (in this case, state it as 10^2 as in choice C).  

Note: Once you do your conversion, you can plug it into your calculator and press "=" to verify that you did not change the number in doing your conversion.

Taking into account the definition of Scientific notation, the correct representation of 702.0 g in scientific notation is option C. 7.020×10² g.

First of all, scientific notation is a quick way to represent a number using powers of base 10. This notation is used to be able to express very large or very small numbers very easily.

The numbers are written as a product:

a×10ⁿ

where:

a is a real number greater than or equal to 1 and less than 10, to which a decimal point is added after the first digit if it is a non-integer number. n = a whole number, which is called an exponent or an order of magnitude. Represents the number of times the point decimal is shifted. It is always an integer, positive if it is shifted to the left, negative if it is shifted to the right.

In this case, to write the number 702.0 in scientific notation, the following steps are performed:

The decimal point is moved to the left as many spaces until it reaches the right of the first digit. This number will be the value of a in the previous expression. Then a = 7.020 The base 10 is written with the exponent equal to the number of spaces that the decimal point moves. This is a positive number because the decimal point is shifted to the left, and it will have a value of n = 2.

So, the correct representation of 702.0 g in scientific notation is option C. 7.020×10² g.

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A sample of aluminum weighs 100 grams and has a volume of 37.03 cm. What is the density of
aluminum?

Answers

Answer:

2.7005 g/cm²

explanation: as we know density=mass/volume

Circle the molecule(s) in the atmosphere that come from animals. (circle all that apply)
a. Carbon dioxide, CO,
b. Helium, He
c. Methane, CH
d. Oxygen, O2

Answers

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 -

a. Carbon dioxide, CO2c. Methane, CH4

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:

Carbon dioxide: during cellular respiration, animals release carbon dioxide as a waste product with energy. This carbon dioxide is removed from the body of animals to the atmosphere.Methane is a gas that is also released by the animals to the atmosphere but in very low concentration or quantity. During the digestion process, methane gas is formed in the digestion tract. methane will be released as burp mainly.

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

a. Carbon dioxide, CO2c. Methane, CH4

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what claim is being made?

Answers

the correct answer is c

Answer:

D

Explanation:

because it's saying the diet soda has more calories then regular soda it's like someone claimed you of doing something you didn't do and they don't know that

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