Which statement about melting and boiling points is true? Question 3 options:

A. As you move down group 7A in the periodic table, the melting and boiling points of the elements decrease.

B. As you move up group 8A in the periodic table, the melting and boiling points of the elements increase

. C. Smaller atoms in group 8A require higher boiling points for the molecules to separate from each other than larger atoms in group 8A.

D. Larger atoms in group 8A require higher boiling points for the molecules to separate from each other than smaller atoms in group 8A.

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:

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

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

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Answer:

3.8

Explanation:

The value of mass is 680 g.

It is defined as mass per unit volume.

Given:-

[tex]Density=13.6\ g/cm^{3} \\Volume=50\ mL[/tex]

Calculate mass as follows:-

[tex]Density=Mass/Volume\\13.6\ g/cm^{3} = Mass/50.0\ mL\\Mass=13.6\ g/cm^{3} \times50.0\ mL[/tex]

Relationship used:-

[tex]1\ cm^{3} =1\ mL[/tex]

[tex]Mass=680\ g[/tex]

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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.

Answer:

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

Explanation:

Answer:

2.7005 g/cm²

explanation: as we know density=mass/volume

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:

Strontium, as opposed to other elements on the periodic table (with the exception of others in the same group/column i.e., the vertical direction), is a good substitute for Calcium because they are in the same group.

Explanation:

This is because elements of the same group behave similarly and have similar properties. This is due to the fact that elements of the same group (in the vertical direction) have the same number of valence electrons.

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:

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

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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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.

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:

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:

True

Explanation:

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

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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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:

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

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:

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

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:

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.

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 Scientist

Explanation:

Answer:

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

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:

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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