Solutions
Which statement is true of pure substance

1. They may contain one type of atom or one type of molecules.
2.they can only contain one type of molecules.
3.they can contain different types of atoms and molecules.
4.they can only contain one type of atom

This is science btw

Answers

Answer 1

Answer:

4

Explanation:

cuz pure substance contain one type of atom,molecule,or cpd.

2 is true but it have wrong grammar,if it contain only one type it must be^^molecule^^


Related Questions

What is the molarity of Na+ ions in a 0.02M sodium phosphate solution?

Answers

Answer:

.06 M NA+

Explanation:

You go from (.02M Na3PO4 / 1) x (3 mole Na+ / 1 mole Na3PO4) = .06 M Na+

what happened if you poured lava on snow​

Answers

Answer:

This is what could happen:

Explanation:

When lava meets ice, the resulting mess can cause flooding, destroy valuable resources and even produce explosions.

Answer:    When lava meets ice, it neither explodes nor tunnels through; rather, it forms strange-looking bubbles.

Explanation:

when the corporation issuing the bonds has the right to redeem the bonds prior to the maturity, the bonds are

Answers

Answer:

Callable or redeemable bonds

Explanation:

"..are bonds that can be redeemed or paid off by the issuer prior to the bonds' maturity date."

What is carbon? What does it do?

Answers

The Short Answer: Carbon is in carbon dioxide, which is a greenhouse gas that works to trap heat close to Earth. It helps Earth hold the energy it receives from the Sun so it doesn't all escape back into space. If it weren't for carbon dioxide, Earth's ocean would be frozen solid.

What mass of water absorbs 6700 J of heat to raise the temperature from 283K to 318K?​

Answers

Answer:

you did not give the specific heat like formula like it takes 1kj to raise 28grams of water by 10 grams

how would separate a mixture of lead 2 chloride and sodium chloride​

Answers

Answer:

lower th

Explanation:

Pb{Cl}_{2})$ is an inorganic

answer:

lower the temperature so the lead chloride settles out of solution

compound which is a white solid under ambient conditions. It is one of the most important lead-based

reagents. It is poorly soluble in water. And it is insoluble in cold water. Sodium chloride is ssolble at all temperature

so lower the temperature

what type of bacteria use the enzyme nitrate reductase to metabolize nitrogen oxides and transform them back to nitrogen gas?

Answers

Denitrifying Bacteria such as Pseudomonas aeruginosa is the type of bacteria that use enzyme nitrate reductase to metabolise nitrogen oxides to nitrogen gas.

Denitrification is the process whereby nitrites or nitrogen oxides is converted to nitrogen gas by a denitrifying Bacteria such as Pseudomonas.

Pseudomonas aeruginosa uses enzyme nitrate reductase to reduce nitrate to nitrite.

Then nitrite is then converted back to nitrogen gas.

Therefore, Pseudomonas aeruginosa is a type of bacteria that uses enzyme nitrate reductase.

Which product in the reaction forms a precipitate? PbSO4 MgCl2 PbMg no precipitate formed

Answers

MgCl2 product in the reaction forms a precipitate because it is solid an insoluble salt and not dissolve in solution and precipitate on the bottom surface of the solution.

What is precipitation reaction?

The chemical reaction in which two ionic bond combine to form an insoluble salt in a aqueous solution is called precipitation reaction.

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Define ionic bond and explain the formation of nacl and mgo

Answers

a.

Ionic bond is a bond in which there is complete transfer of valence electrons between atoms.

The atom that loses the valence electron is called the electron donor while the atom that accepts the electron is called the electron acceptor.

Ionic bond usually occurs between metals and non metals.

Ionic bond is a bond in which there is complete transfer of valence electrons between atoms.

b.

The force of attraction between Na⁺ and Cl⁻ forms the ionic bond.

In the formation of NaCl, Na has one valence electron in its outermost shell and Cl needs one electron to complete the stable octet configuration. Na donates its valence electron to Cl to form the ionic bond. So, the Na atom becomes positively charged with a charge of +1 while the Cl atom becomes negatively charged with a charge of -1.

Since the atoms are now charged, the force of attraction between them forms the ionic bond.

c.

The force of attraction between Mg²⁺ and O²⁻ forms the ionic bond.

In the formation of MgO, Mg has two valence electrons in its outermost shell and O needs two electrons to complete the stable octet configuration. Mg donates its two valence electron to O to form the ionic bond. So, the Mg atom becomes positively charged with a charge of +2 while the O atom becomes negatively charged with a charge of -2.

Since the atoms are now charged, the force of attraction between them forms the ionic bond.

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An ionic or electrovalant bond is a type of chemical bond, which is formed  from two ions (charged atoms by loosing or gaining electrons) having opposite charges.

Ionic bonds are formed from the transfer of electrons from one atom to another. As the electrons are transferred there occurs a positively charged ions (cations) and a negatively charged ions (anions). These ions are held together in a crystal lattice structure by the strong electrostatic attraction between the positively charged cations and negatively charged anions.

The electrons are transferred as the atoms have tendencies to achieve a stable electronic configuration. They do this to attain a stable atomic structure. By transferring the electrons they attain their octet or duplet.

Sodium chloride(NaCl) is formed when the atom of sodium combines chemically with chlorine atom to generate an ionic compound.

Since sodium has an atomic number of 11, its electronic configuration is 2, 8, 1. There is only one electron in the outermost shell of a sodium atom. Therefore, the sodium atom gives one electron to produce the sodium ion Na⁺.

Chlorine has an atomic number of 17. Hence, its electronic configuration is 2, 8, and 7. The chlorine atom contains seven electrons in its outermost shell and requires one more electron to create the inert gas’s stable, eight-electron configuration. Consequently, a chlorine atom accepts one electron and creates the negatively charged chloride ion (Cl⁻).

When sodium interacts with chlorine, it donates its outermost electron to the chlorine atom, forming a sodium ion (Na⁺) and a chloride ion (Cl⁻) by accepting an electron. The strong electrostatic force of attraction between the newly created ions, holds sodium and chloride ions together to create sodium chloride, Na⁺Cl⁻ or NaCl.

Similarly in the case of Magnesium Oxide (MgO) is formed from the chemical interactions of Magnesium and oxygen atoms, leading to the formation of an ionic compound.

Since magnesium has an atomic number of 12, its electrical configuration is 2, 8 and 2, there is just 2 electrons in the outermost shell of a Magnesium atom. Therefore, the magnesium atom gives two electron to produce the Magnesium ion Mg²+ .

Oxygen has an atomic number of 8. Hence, its electronic configuration is 2 and 6, the oxygen atom contains 6 electrons in its outermost shell and requires 2 more electron to create the inert gas’s stable, eight-electron configuration. Consequently, a oxygen atom accepts 2 electronelectrons and creates the negatively charged oxide ion (O²-).

When magnesium interacts with oxygen, it donates its outermost electrons to the oxygen atom, generating a Magnesium ion Mg²+ .  And an oxygen ion (O²⁻) by acquiring 2 electrons. The attractive electrical force holds magnesium and oxygen   ions together to create sodium chloride,        Mg²⁺ O²⁻ or MgO.

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A gas occupies a volume of 120 mL at 700 mm Hg. What will happen to the volume of the gas if the pressure is changed to 1500 mm Hg at constant temperature

Answers

Answer:

56 mL

Explanation:

The new volume can be found by using the formula for Boyle's law which is

[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

From the question we have

[tex]V_2 = \frac{700 \times 120}{1500} = \frac{84000}{1500} = \frac{840}{15} \\ = 56[/tex]

We have the final answer as

56 mL

Hope this helps you

Explain how the heat and phase changes affects the environment? Give examples.
(5-7 sentences)​

Answers

Energy is required to change the phase of a substance, such as the energy to break the bonds between molecules in a block of ice so it may melt.
During a phase change energy my be added or subtracted from a system, but the temperature will not change. The temperature will change only when the phase change has completed. No temperature change occurs from heat transfer if ice melts and becomes liquid water (i.e., during a phase change). For example, consider water dripping from icicles melting on a roof warmed by the Sun. Conversely, water freezes in an ice tray cooled by lower-temperature surroundings. Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart so that the molecules can move around at comparable kinetic energies; thus, there is no rise in temperature.

What is atomic mass? the mass of the atom based on the mass of an atom of hydrogen-1 the mass of an atom based on the mass of an atom of carbon-12 the mass of the atom based on the mass of an atom of oxygen-16 the mass of an atom based on the number of electrons

Answers

Answer:

The mass of an atom based on the mass of an atom of carbon-12

Explanation:

What defines an element?

Answers

Explanation:

each of more than one hundred substances that cannot be chemically interconverted or broken down into simpler substances and are primary constituents of matter. Each element is distinguished by its atomic number, i.e. the number of protons in the nuclei of its atoms.

15
The diagram below shows a landscape
Upper atmosphere
Ocean
Where in the diagram would the air pressure be
the greatest

Answers

Answer:

No diagram no help

Explanation:

bond angle of SO2 H2S SO3​

Answers

Explanation:

In SO2 , the bond angle is 119^∘ whereas in SO3 , the bond angle is 120^∘ .H2S = 92.1°

Answer:

In SO2 , the bond angle is 119^∘ whereas in SO3 , the bond angle is 120^∘ .

Explanation:

S atom in both SO2 and SO3 is sp^2-hybridized.

There are 3 bonding sets of electrons and one non-bonding pair on the sulphur. So the shape is based on a tetrahedral structure - but the extra repulsion of the non-bonding pair will decrease the O-S-O angles by a few degrees from the 'perfect' tetrahedral angle.

The bonding in SO3 can be described as a combination of 3 resonance forms of 1 double and 2 single bonds. The SO2 molecule has a dipole moment, The starting point of 109.5 degrees is only applicable for 4 electron regions round the central atom. In SO2, we have 2 double bonds and one lone pair ; 3 electron regions so the default angle is 120 degrees. The extra repulsion of the lp vs double bonds accounts for reduction to 119. S atom in both SO2 and SO3 is sp2-hybridized. But it is related to dipole moment and assertion is the explanation from bent angle so here reason is unable to give explanation of assertion.

How are polypeptides and proteins similar?
A. They are both made of amino acids.
B. They are both polysaccharides.
O C. They are both nucleic acids.
D. They are both made of carbohydrates.

Answer is A

Answers

Answer:

The answer is A.

Explanation:

They are both made of amino acids.

Unlike solids and liquids, gases can be compressed. How is this physical characteristic of gases beneficial to society?

Answers

Gases have three characteristic properties: (1) they are easy to compress, (2) they expand to fill their containers, and (3) they occupy far more space than the liquids or solids from which they form. An internal combustion engine provides a good example of the ease with which gases can be compressed.

A student dissolved some crystals of a salt in water.
The student added sodium hydroxide solution to the salt solution
The student added sodium hydroxide until it was in excess
Describe what the student would see if the salt contained calcium ions

Answers

That’s not nice you can’t be taking points

Under Normal Conditions no reaction will be seen between Calcium ions (Ca⁺), NaCl (salt solution) and NaOH(sodium hydroxide).

What is a double replacement reaction ?

In a double replacement reaction , the compounds present switch cation and anion to form new compounds.

But here in NaOH(sodium hydroxide) and NaCl (salt solution) the cation sodium ion Na⁺, of both the compounds is same so the end result will be same .

There will be no net reaction .

But if excess Sodium Hydroxide is added to the solution , we will see precipitate of NaCl , salt forming.

If Salt contained Ca⁺ ions , firstly NaCl will only combine with Ca⁺ ions in special conditions as Na⁺ ions are more reactive than Ca⁺ ions.

On addition of NaOH we would observe no change in normal conditions due to above stated reason .

In special conditions following reaction takes place ,in normal condition the reaction follows reverse direction.

Ca + 2 NaOH ← Ca(OH)₂ + 2 Na

Hence under Normal Conditions no reaction will be seen between Calcium ions , NaCl (salt solution) and NaOH(sodium hydroxide).

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State the term used for the light that is transmitted when complex ions absorb wavelengths of visible light. Give the answer using two words only (and be careful with spelling).

Answers

Answer:

complementary colour

Explanation:

The complementary colors are used for the light that is transmitted when complex ions absorb wavelength of visible light.

What is complementary colors?

Complementary colors are color pairs that cancel each other whenever combined and mixed, resulting in a grayscale color either white or black. They offer the most contrast for the those two hues when put adjacent to each other. Colors that are complementary are sometimes known as "opposite colors."

What is light?

Light, often known as visible light, is electromagnetic radiation that falls within the region of the electromagnetic spectrum which the human eye can perceive.

Therefore,  the complementary colors are used for the light that is transmitted when complex ions absorb wavelength of visible light.

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If Temperature 25 C and volume is 117.5 cm³. Explain volume temperature relationship using Charles’s law.

(No links or else I'll report.
Don't answer if u dont know.)

Thank You.​

Answers

Explanation:

According to Charles law : V/T=k (constant).

the volume temperature relationship will be

V/T = 117.5/25 = 4.7

hope this helps you.

Which sentence from the article BEST describes HOW fireworks produce colors in the sky?
(A)
It needs an oxidizer, a fuel and a chemical mixture to produce the color.
(B)
Over the years, scientists have staged various chemical reactions to produce fireworks of different
colors.
(C)
The color of that light depends on what chemical elements are present.
(D)
When the casing explodes, pellets containing the chemical color mixtures fly out.

Answers

The answer is Abecaue it is the most specific on how

Fireworks need an oxidizer, fuel, and a chemical mixture to produce the colour in the sky. Therefore, option (A) is correct.

How do colours come from firecrackers?

The chemicals which are used in crackers are the main reason for the colours in the sky. The colours in the fireworks come from different compounds which are the binder and the colourant. The colourant chemicals provide the colours in the firework while the binder is the agent that binds the fuel and is responsible to burn up the colourant in the firework.

The colourants in the firecrackers can be generated with the use of various metallic salts. These salts can be defined as iconic compounds which possess an anion or an acid and a cation or a base. The metal salts are responsible for generating intense colours when they are burned.

For example, if use calcium salts in the firework will produce an orange colour, and copper salts will produce a bright blue colour.

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What is the differences between solids liquids and gases on a molecular level apes.

Answers

The difference is i dont know the answer i need points thank you

Which of the following correctly lists the particles in order from least massive to most massive.

A. electron, proton, hydrogen atom, helium atom
B. proton, electron, hydrogen atom, helium atom
C. proton, helium atom, hydrogen atom, electron
D. hydrogen atom, electron, helium atom electron​

Answers

Answer:

The ans is : A. Electron, proton, hydrogen atom, helium atom.

An atom consist of sub atomic particles. The order of particles from least massive to most massive is electron, proton, hydrogen atom, helium atom. The correct option is A.

What are subatomic particles?

The particles which are smaller in size than the atom are known as the sub atomic particles. An atom generally contains three sub atomic particles, they are protons, electrons and neutrons. The electrons revolve around the nucleus whereas the protons and neutrons are present at the center of the nucleus.

The protons are positively charged particles whereas the electrons are negatively charged. The neutrons are chargeless. The atomic number of 'H' atom is 1 and that of 'He' atom is 2.

The mass of e⁻ is 9.1 × 10⁻³¹ kg, proton is 1.67 × 10⁻²⁷ kg, 'H' atom is 1.66 × 10⁻²⁴ g, 'He' is 4 g. Thus the order is:

electron, proton, hydrogen atom, helium atom

Thus the correct option is A.

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Water (H2O) is a liquid at room temperature, while carbon dioxide (CO2) is a gas at room temperature. Why? Choose the two statements that apply.

Answers

Water has relatively strong hydrogen bonds holding the molecules together but CO2 has only dispersion forces acting as intermolecular forces. The weaker intermolecular forces explains why CO2 is a gas whereas H2O is a liquid at room temperature

An endothermic process may be spontaneous if ______. Multiple choice question. the endothermic process results in a precipitation of a crystalline solid from a liquid solution the endothermic process converts a gas reactant into a liquid or solid product the product particles have more freedom of motion than the reactant particles the product particles have less freedom of motion than the reactant particles

Answers

An endothermic process may be spontaneous if: C. the product particles have more freedom of motion than the reactant particles.

An endothermic reaction can be defined as a type of chemical reaction in which heat energy is absorbed from the environment.

Generally, heat energy is absorbed in a chemical reaction when the energy of the products is greater (more) than the energy of the reactants and this is referred to as an endothermic reaction.

Similarly, an endothermic process may be spontaneous when the product particles have more freedom of motion than the reactant particles.

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How do weak intermolecular bond strengths affect the melting and boiling point of a substance?

The melting point is lower, but the boiling point is higher.

Both the melting point and boiling point are lower.

The melting point is higher, but the boiling point is lower.

Both the melting point and boiling point are higher.

Answers

Considering the definition of intermolecular bond, the correct answer is second option: Both the melting point and boiling point are lower.

The molecules of covalent compounds can be held together through electrostatic interactions known as "intermolecular forces", which are characterized by holding more than one molecule together. Therefore, they are related to chemical bonds, which have the goal of making molecules stick together or separate.

In other words, intermolecular forces or bonds are those interactions that hold molecules together. These are electrostatic forces.

The presence of these forces explains, for example, the properties of solids and liquids.

They differ from intramolecular forces, because of these, they correspond to interactions that hold the atoms in a molecule together. In general, intermolecular forces are much weaker than intramolecular forces.

On the other side, the melting point is the temperature at which a substance goes from solid to liquid at a given pressure. Similarly, the boiling point is the temperature at which the substance passes from a liquid to a gaseous state.

Finally, the more intense the intermolecular forces, the higher the melting point and the boiling point of a substance because these are the forces that must be overcome to separate them.

In summary, the correct answer is second option: Both the melting point and boiling point are lower.

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Please help? It’s for chem

Answers

Answer:

O-H

Explanation:

It is polar covalent bond, because the hydrogen atom has electronegativity about 2.6, and the oxygen atom, electronegativity about 3.6. When the difference in electronegativity of the atoms is between 0.4 and 1.7, the result is a polar covalent bond.

If a particular utility burned 6.17 million tons of coal that was 2.00% sulfur by weight, how many tons of sulfur dioxide was emitted?

Answers

246800 tons of sulfur dioxide was emitted by the utility company who burned 6.17 million tons of coal.

6.17 million tons of coal contain 2.00% sulfur, hence the weight of sulfur is:

Weight of sulfur = 2% of 6.17 million tons = 0.02 * 6170000 = 123400 tons

123400 tons of sulfur is found in 6.17 million tons of coal

The weight of sulfur dioxide is twice that of sulfur, hence:

Amount of sulfur dioxide emitted = 2 * 123400 tons  = 246800 tons

246800 tons of sulfur dioxide was emitted.

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Is it possible to move the atoms close enough that the nuclei come in contact?

Answers

Answer:

I believe not.

Explanation:

From what I have been told atoms can never come into contact beyond the electron barrier.

What volume does 0.25 moles of oxygen gas occupy at STP ?

Answers

Answer:

[tex]\boxed {\boxed {\sf 5.6 \ L \ O_2}}[/tex]

Explanation:

We are asked to find the volume of 0.25 moles of oxygen gas.

At standard temperature and pressure or STP, one mole of any gas has a volume of 22.4 liters.

We want to convert 0.25 moles of oxygen gas or O₂ to liters. We will use dimensional analysis, so we must set up a conversion factor.

[tex]\frac {22.4 \ L \ O_2}{1 \ mol \ O_2}[/tex]

We are converting 0.25 moles of oxygen gas, so we multiply the conversion factor by this value.

[tex]0.25 \ mol \ O_2 *\frac {22.4 \ L \ O_2}{1 \ mol \ O_2}[/tex]

The units of moles of oxygen gas cancel.

[tex]0.25 *\frac {22.4 \ L \ O_2}{1 }}[/tex]

[tex]0.25 * 22.4 \ L \ O_2[/tex]

[tex]5.6 \ L \ O_2[/tex]

0.25 moles of oxygen gas occupy 5.6 liters at standard temperature and pressure.

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