Which term describes a pure substance that is
composed of only one type of atom?
Answers
The term that describes a pure substance that is composed of only one type of atom is an element.
An element is a substance that cannot be broken down into simpler substances by chemical reactions. Each element has a unique number of protons in the nucleus of its atoms, which gives it a specific atomic number. For example, the element carbon has an atomic number of 6, meaning that each carbon atom has 6 protons in its nucleus.
Elements are the building blocks of all matter, and there are currently 118 known elements, ranging from hydrogen (which has an atomic number of 1) to oganesson (which has an atomic number of 118). Elements can exist in various states of matter, including solids, liquids, and gases, depending on their temperature and pressure.
Pure substances, like elements, have uniform properties and composition throughout. This means that every particle of an element has the same chemical and physical properties, such as its melting point, boiling point, and density. In contrast, a mixture is composed of two or more substances that are physically combined but not chemically bonded.
Mixtures can be separated into their component parts by physical means, while pure substances cannot.
In summary, an element is a pure substance that is composed of only one type of atom. It cannot be broken down into simpler substances by chemical reactions and has uniform properties and composition throughout.
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Related Questions
Can grasshoppers fly?
Answers
Answer:
Yes, because they have strong wings..
a sample of o2 with an initial temperature of 50.0c and a volume of 105 l is cooled to -25c. the new pressure is 105.4 kpa and the new volume is 55.0 l. what was the initial pressure of the sample?
Answers
To solve this problem, we can use the combined gas law, which relates the initial and final states of a gas sample undergoing temperature and volume changes. The formula for the combined gas law is:
(P1 * V1) / (T1) = (P2 * V2) / (T2)
Where:
P1 = Initial pressure
V1 = Initial volume
T1 = Initial temperature
P2 = Final pressure
V2 = Final volume
T2 = Final temperature
Let's plug in the given values:
P1 = Unknown
V1 = 105 L
T1 = 50.0°C = 50.0 + 273.15 K = 323.15 K
P2 = 105.4 kPa
V2 = 55.0 L
T2 = -25°C = -25.0 + 273.15 K = 248.15 K
Now we can solve P1:
(P1 * 105 L) / 323.15 K = (105.4 kPa * 55.0 L) / 248.15 K
Rearranging the equation to solve for P1:
P1 = [(105.4 kPa * 55.0 L) / 248.15 K] * (323.15 K / 105 L)
P1 ≈ 156.49 kPa
Thus, the initial pressure of the sample was approximately 156.49 kPa.
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Calculate the medullary index of a hair whose diameter is 110
microns wide and whose medulla measures 58 microns. Is this
a human or animal hair?
Answers
The medullary index of hair is the ratio of medullary diameter to the diameter of hair. Thus the medullary of hair with 110 microns and medulla diameter of 58 microns is 0.533. This is an animal hair.
What is hair medullary index?Medullary index of hair is the ratio of diameter of the medullary part and the diameter of the hair strand. From this value, we can identify whether the sample hair is of humans or animals.
Hair is made proteins called keratin. The protein structure of hair vary from human to human even one hair strand to the other and similar way it is different in animal hair too.
The hair strand of humans are thin than the hair strands of animals. Thus the medullary index of humans is 0.333 or less. If the index is 0.50 or greater it is of animals.
Here the diameter of hair is 110 microns and that of medulla is 58 microns thus medullary index is 58/110 = 0.55 microns. Which means that it is an animal hair.
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40.0 L of oxygen were collected at 10°C and 758 mm of Hg.
Calculate its volume at STP
Answers
Answer:
38.48 L. Good luck on your test :)
Explanation:
I clicked it and it was right.
Iodine adds to the double bonds in fatty acids (one iodine molecule per double bond). How many double bonds are in a molecule of arachidonic acid (Molar mass
Answers
Answer:
To test if a lipid is saturated or unsaturated iodine is added. If the iodine changes from brown to clear the lipid is unsaturated. If the iodine does not change colors the lipid is saturated. To test for the degree of lipid saturation iodine is added to the unsaturated lipid.
Explanation:
Identify the situations that have an unbalanced force. Check all that apply.
A- A baseball speeds up as it falls through the air.
B- A soccer ball is at rest on the ground.
C- An ice skater glides in a straight line at a constant speed.
D- A bumper car hit by another car moves off at an angle.
E- A balloon flies across the room when the air is released.
Answers
Answer:
A baseball speeds up as it falls through the air.
Yes. Forces on the balloon are unbalanced.
The balloon is speeding up, so we know that the downward force
of gravity is stronger than the upward force of air resistance.
A soccer ball is at rest on the ground.
No. The ball is not accelerating, so we know that the forces on it
are balanced.
The downward force of gravity on the ball and the upward force
of the ground are equal.
An ice skater glides in a straight line at a constant speed.
No. The skater's speed and direction are not changing, so he is not
accelerating. That tells us that the forces on him are balanced.
A bumper car hit by another car moves off at an angle.
Yes. The direction in which the car was moving changed.
That's acceleration, so we know that the forces on it are unbalanced,
at least at the moment of impact.
A balloon flies across the room when the air is released.
Yes. The balloon was not moving. But when the little nozzle was
opened, it started to zip around the room. So its speed changed.
And, as it goes bloozing around the room, its direction keeps changing too.
There's a whole lot of acceleration going on, so we know the forces on it
are unbalanced.
why is methane the simplest alkane?
Answers
dispersion forces are a type of intermolecular force that exists between only polar molecules . dispersion forces are the strongest type of intermolecular force. however, dispersion forces are stronger for choose... molecules because they are more choose... .
Answers
Dispersion forces are a type of intermolecular force that exists between only polar molecules . dispersion forces are the strongest type of intermolecular force. however, dispersion forces are stronger for larger molecules because they are more polarizable .
What is dispersion forces?
The least powerful intermolecular force is the London dispersion force. When the electrons in two nearby atoms occupy positions that cause the atoms to temporarily form dipoles, the consequence is the London dispersion force, a transient attractive force. The term "induced dipole-induced dipole attraction" is frequently used to describe this effect. When the temperature is sufficiently dropped, London forces—attractive forces—cause nonpolar substances to condense into liquids and to freeze into solids.
When an atom or molecule's electrons are dispersed asymmetrically around the nucleus, an instantaneous (temporary) dipole can form due to the electrons' continual mobility.
Whether they are polar or nonpolar, all molecules exhibit dispersion forces.
Atoms and molecules that are bigger and heavier show larger dispersion forces than those that are smaller and lighter.
The valence electrons are, on average, farther from the nucleus in a larger atom or molecule than in a smaller atom or molecule. They can more easily create transient dipoles because they are not held as tightly.
The term "polarizability" refers to how easily the electron distribution around an atom or molecule can be altered.
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Mrs. Scott did a demonstration for her class. She used tongs to hold a piece of steel wool in the flame of a Bunsen burner. The steel wool caught on fire and began to burn. Mrs. Scott removed the steel wool from the flame and allowed it to burn for 20 minutes.
Later, Mrs. Scott took a piece of the burned steel wool and held it in the flame of the Bunsen burner. It did not catch on fire.
Make a claim about whether the steel wool underwent a chemical reaction while burning. Support your claim with evidence from the demonstration.
Answers
The demonstration shows that steel wool burned chemically.
From the demonstration, steel wool burned chemically. The supporting evidence is:
1. Combustion: Bunsen burner flame ignited steel wool. A material combines with oxygen to produce heat, light, and gases or new compounds in combustion. Steel wool burning implies a chemical reaction.
2. Steel wool burned for 20 minutes. This prolonged burning signals a chemical process. Shape and size alterations rarely last this long.
3. Failure to Ignite: A piece of charred steel wool held in the flame again did not ignite. This implies that the initial chemical reaction that caused the steel wool to ignite was irreversible. After a chemical reaction consumes the reactants, it may not happen again without replacing them.
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______ gas is used in gas filled windows to improve thermal performance. A ) Argon B ) Nitrogen C ) Hydrogen D ) Carbon dioxide.
Answers
Answer:
Argon
Explanation:
Argon is the gas that is used most often by window manufacturers to displace the air between the panels in windows. Argon is non-toxic, inert, clear, and odorless. Its thermal conductivity is roughly 67% that of air and it’s inexpensive, making it an attractive gas fill
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Jenna took an open bowl of leftover mashed potatoes from the refrigerator and noticed a difference in smell. She determined that chemical changes occurred since the potatoes were first placed there.
Which observations most likely led to Jenna’s conclusion?
Answers
Answer:
The change in smell
Explanation:
chemical reactions ccan lead to change in temperature, change in color and also change in smell
3
A student has a 5. 00 gram sample of calcium chloride (CaCl2) solid. How many moles of calcium chloride are
contained in this sample?
Answers
The number of moles of calcium chloride ( CaCl₂) are contained in the given sample is 0.045 moles.
Given that :
The mass of the calcium chloride, CaCl₂ = 5 g
The molar mass of the calcium chloride, CaCl₂ = 110.98 g /mol
The number of moles can be calculated by the formula given below :
The number of moles = mass / molar mass
where,
Mass = 5 g
Molar mass = 119.98 g/mol
The number of moles = 5 g / 110.98 g /mol
The number of moles = 0.045 moles.
The moles of the calcium chloride , CaCl₂ is 0.045 mol.
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If 65 marbles have a mass of 117g, what
would the mass of 60 marbles be?
Answers
Answer:
Hi
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Explanation:
65 marbles ------> 117g
60 marbles -------> xg
Cross multiply
65x = 117 ×60
x= 117 × 60
-----------
65
x=108 g
Student added a strip of aluminium metal in aqueous copper(2)Sulfate but no reaction occured. Suggest a reason why.
Answers
Answer:
See Explanation
Explanation:
It is a common observation that a strip of aluminium metal in aqueous copper(II)Sulfate does not show any visible reaction. Aluminium is normally expected to displace copper in solution since it is higher than copper in the electrochemical series.
The reason for this is that aluminium forms an oxide film around its surface which prevents reaction with aqueous copper(II)Sulfate. This oxides film protects the aluminium surface such that it is now unable to react with the aqueous copper(II)Sulfate
4. Plant cells have large, round vacuoles they primarily use for-
Answers
Plant cells have large, round vacuoles they primarily use for water storage so that will be option A.
A vacuole is a membrane-bound organelle found in plant, fungus, and animal cells, as well as certain protist, animal, and bacterial cells. Vacuoles are simply confined compartments filled with water holding inorganic and organic molecules in solution, including enzymes, while in certain situations they may also include solids that have been absorbed.
Vacuoles are generated by the fusing of several membrane vesicles and are just bigger versions of these. The organelle has no fixed form or size; its structure changes depending on the needs of the cell.
The role and relevance of vacuoles vary substantially depending on the kind of cell in which they are found, with plants, fungi, and some protists having far more prominence than animals and bacteria. In general, the vacuole performs the following functions:
Isolating materials that might be toxic or pose a risk to the cellstoring waste productsWater storage in plant cellsLearn more about Vacuoles:
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Complete question:
Plant cells have large, round vacuoles they primarily use for -
A) water storage
B) energy production.
C) protein synthesis.
D) waster removal
what is the ph of a 0.25-m solution of ca(oh)2? (give the answer in three sig figs)
Answers
The pH of a 0.25-M solution of \(Ca(OH)_{2}\) is 12.5.
The pH of a 0.25-M solution of \(Ca(OH)_{2}\) can be calculated using the formula:
14 - pOH = pH
The pOH of the solution can be found using the formula:
pOH = - log [\(OH^{-}\)]
Where [[\(OH^{-}\)] is the concentration of the hydroxide ion in the solution.
The concentration of hydroxide ions in a 0.25-M solution of \(Ca(OH)_{2}\) can be calculated as follows:
0.25 M \(Ca(OH)_{2}\) solution dissociates into 0.5 M \(OH^{-}\) ions[\(OH^{-}\)] = 0.5 M
\(OH^{-}\) is a strong base; therefore, the concentration of the hydroxide ion is equivalent to its molarity.
So,
pOH = - log [\(OH^{-}\)]
= - log (0.5)
= 0.3010
Now, we can use the equation:
14 - pOH = pH
= 14 - 0.3010
= 13.699 ≈ 12.5
Therefore, the pH of a 0.25-M solution of \(Ca(OH)_{2}\) is 12.5.
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Which of the following correctly compares glass A and glass B?
A black line splitting the image into two parts. On the left hand side is glass A that is almost full. On the right side is glass B that is half full.
Question 13 options:
Glass A has the same mass as glass B.
Glass A has a greater mass than glass B.
Glass A has the same amount of liquid as glass B.
The liquid in both glasses takes up the same space.
Answers
Answer:
Glass A has a greater mass than glass B
Answer:
Glass A has a greater mass than Glass B
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All of the following are qualitative tests that are often used to identify unknown ionic compounds except __________
Answers
All of the following are qualitative tests that are often used to identify unknown ionic compounds except titration.
Qualitative tests are conducted to determine the presence or absence of certain ions or compounds in a sample based on their characteristic reactions. Common qualitative tests include flame tests, precipitation reactions, color changes, and gas evolution tests.
Titration, on the other hand, is a quantitative technique used to determine the concentration of a specific substance in a solution by reacting it with a standardized solution of another substance. It is not typically used as a qualitative test for identifying unknown ionic compounds.
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What is the signifcence of H, 2H, 3 H, H2, 2 He, Na,
Snaco, ouco, CO, 460?
Answers
H=hydrogen,H2=hydrogen atoms,
Why do some bodies in the Solar System maintain countless well-preserved indications of impacts on their surface
even after many millions of years? Give some examples and explain in detail how at least 2 factors contribute to this
Answers
Answer:
There are several factors that contribute to the preservation of impact craters on the surface of bodies in the Solar System.
One factor is the lack of erosion or weathering on these bodies. Many of the bodies in the Solar System, such as the Moon and many of the outer planets' moons, do not have atmospheres or hydrospheric systems (like oceans, lakes, or rivers) that can erode or weather the surface over time. This means that the surface of these bodies is not subjected to the same types of processes that can wear away or smooth out surface features on Earth. As a result, impact craters and other surface features can remain well-preserved for millions of years.
Another factor that can contribute to the preservation of impact craters is the presence of a surface layer of material that is resistant to erosion. For example, on the Moon, the surface is covered by a layer of fine-grained dust called regolith, which is made up of small rocks and particles that have been ground up by impact and other processes. This regolith layer is relatively soft and easily disturbed, but it also acts as a protective layer that can preserve the underlying surface features. Similarly, on some of the outer planets' moons, there may be a layer of ice or other materials that can act as a protective layer and preserve impact craters and other surface features.
Examples of bodies in the Solar System that have well-preserved impact craters include the Moon, Mars, and many of the outer planets' moons, such as Europa and Ganymede. The lack of erosion and the presence of protective surface layers on these bodies have allowed them to maintain countless well-preserved indications of impacts on their surfaces even after many millions of years.
Explanation:
To solve this, we must know each and every concept behind solar system. Therefore, impact craters enable scientists to investigate the geological history of a planet.
What is solar system?The Solar System is composed of the Sun and the objects that orbit it. It was created by the gravitational collapse of a massive interstellar molecular cloud 4.6 billion years ago. The Sun contains the vast bulk of the system's mass (99.86%)
Several processes contribute to the preservation of impact craters on the surfaces of Solar System worlds. The absence of erosion or weathering on these bodies is one cause. Another aspect that can aid in the preservation of impact craters is the existence of an erosion-resistant surface layer of material.
Therefore, impact craters enable scientists to investigate the geological history of a planet.
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The table shows the nature of the reactants and products formed in a certain type of chemical reaction. Nature of Reactants and Products Reactants Products Ionic compound + Ionic compound Ionic compound + Ionic compound Which of the following is true about this type of chemical reaction? (4 points) Group of answer choices It is a single replacement reaction, and all four compounds are different. It is a double replacement reaction, and all four compounds are different. It is a single replacement reaction, and each compound has the same set of ions. It is a double replacement reaction, and each compound has the same set of ions.
Answers
The given reaction is a double replacement reaction; option B.
What is a chemical reaction?A chemical reaction is a reaction in which chemical changes occurs in the atoms of reactants which results in the formation pf products.
The given reaction is as follows:
Ionic compound + Ionic compound ---> Ionic compound + Ionic compoundSince exchange of ions occur, it is a double replacement reaction.
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How many carbon atoms are represented by the model below?
A. 12
B. 6
C. 5
D. 4
Answers
The carbon atoms represented by the model are Option B. 6
The given image represents the structure of hexane, which is an organic compound with the chemical formula C6H14. Therefore, the number of carbon atoms represented by the model below is 6, which is option B. The structure of hexane consists of six carbon atoms and 14 hydrogen atoms. It is an alkane that belongs to the class of saturated hydrocarbons, which means that its carbon atoms form single covalent bonds with other atoms.
Hexane is a colorless, odorless liquid that is highly flammable. It is commonly used as a solvent in various industries, such as rubber, textile, and leather. In addition, hexane is also used as fuel in some engines, such as model airplanes and lawnmowers. In summary, the given image represents the structure of hexane, which is an organic compound that consists of six carbon atoms and 14 hydrogen atoms. The number of carbon atoms represented by the model is 6. Therefore, Option B is Correct.
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A 100.0 g sample of sugar contains carbon, hydrogen, and oxygen. The sample contains 40.0 g of carbon and 53.3 g of oxygen. What mass of hydrogen is in the sample?
Answers
Answer:
I think this is it.
Explanation:
As all the mass of other molecules are given and we have to find the mass of hydrogen so total subtracted by carbon and oxygen.
I only need the answer to numberr 4
Answers
what color does blue and cyan pigment make?
Answers
Answer:
Teal
Explanation:
Blue lightens the cyan.
What is the volume of 2.00 moles of an unknown gas at STP?
O2.00 L
0 11.2L
0 44.8L
O 22.4L
Answers
A 1.00 L sample of a gas has a mass of 1.92 g at STP. What is the molar mass (molecular weight) of the gas
Answers
Answer:
The answer is below
Explanation:
Avogadro stated that "Equal volumes of all gases at the same temperature and pressure contain the same number of molecules". Hence at standard temperature and pressure 1 mole of a gas occupies 22.4 liters of volume.
1 mol = 22.4 liters
Given a gas with 1 L and mass of 1.92 g at STP.
number of moles = 1 L / (22.4 L / mol) = 0.0446 mol
The molar mass = mass of gas / number of moles
molar mass = 1.92 g / 0.0446 mol
molar mass = 43.008 g / mol
Given:
Mass = 1.92 gSample of gas = 1.00 LNow,
Number of moles will be:
= \(\frac{1 \ L}{22.4 \ L/mol}\)
= \(0.446 \ mol\)
hence,
The molar mass,
= \(\frac{Mass \ of \ gas}{Number \ of \ moles}\)
By putting the values,
= \(\frac{1.92}{0.446}\)
= \(43.008 \ g/mol\)
Thus the answer above is correct.
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Question 7 of 25
Lighting a match is an example of what kind of energy conversion?
O A. Chemical potential energy being converted to heat energy
B. Kinetic energy being converted to chemical potential energy
C. Chemical potential energy being converted to kinetic energy
D. Gravitational potential energy being converted to heat energy
Answers
Answer:
A
Explanation:
APEX
Lighting a match is an example of chemical potential energy being converted to heat energy. The correct option is A.
What is the conversion of energy?Conversion of energy is when the energy is converted from one form into another form. When chemical or physical reactions occur, there is always a conversion of energy from one form to another.
When we match a light, there is a chemical, Phosphorous sulfide which is rubbed against other chemical, and react and produce fire, so it is converted into heat energy.
Thus, the correct option is A. Chemical potential energy is converted to heat energy regarding lighting a match.
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Aluminum + hydrochloride acid yield aluminum chloride + hydrogen gas
What’s the balanced equation?
Answers
Aluminum + hydrochloride acid yield aluminum chloride + hydrogen gas therefore the balanced equation is 2Al+6HCl→2AlCl₃+3H₂.
What is a Chemical reaction?This is referred to as the process in which one or more substances which are called the reactants, are converted to one or more different substances known as the products and it involves the exchange of electrons between elements.
In this scenario, when Aluminum and hydrochloride acid reacts they form aluminum chloride and hydrogen gas which is the product and the equation can be seen above.
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3. How many protons do the following have?
Calcium
Gold
Copper
Iron
Answers
Answer:
calcium=20
gold=79
copper=29
iron=26
Explanation: