Answer:
The correct option is;
It contains 6.02 × 10²³ particles of a given substance
Explanation:
A mole of substance is the standard scientific unit of measurement for the quantity of the substance which is made up of a large number of small particles such as molecules, ions, atoms, electrons or other entities.
The General Conference on Weights and Measures defines the mole as the amount of a substance that contains 6.02214076 × 10²³ units of entities
The number 6.02214076 × 10²³, is also known as Avogadro's number.
The statement which correctly describes the mole is; it contains 6.02 × 10^23 particles of a given substance.
The mole refers to the amount of substance that contains the same number of elementary entities as 12 g of carbon - 12. According to Avogadro's law, the number of elementary entities in a substance is 6.02 × 10^23. These elementary entities could be atoms, ions, molecules etc.
Therefore, the statement which correctly describes the mole is; it contains 6.02 × 10^23 particles of a given substance.
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3. Prepare a saturated solution of common salt in hot water. Suspend a thick cotton wick into this solution. Keep it undisturbed for a few days. You will find that common salt crystals will deposit on the wick. Is the change physical or chemical?
Answer:
physical
Explanation:
The change is physical.
A physical change involves a reversible change to the physical properties of substances, whereas a chemical change involves an irreversible change to the chemical properties of substances through a chemical reaction.
The dissolution of common salt is a physical change because the common salt can be retrieved by evaporating off the water. This is what was manifested by the deposition of common salt crystals on the wick.
In science class, Jake mixed water with differing amounts of an unknown liquid. After mixing the liquids, he heated 20 milliliters (ml) of each mixture and observed how quickly it boiled. The table shows his results.
According to the question, each mixture decrease the boiling point of the water.
What is boiling point ?Boiling temperature is defined as the temperature at which liquid change into a vapour at the atmospheric pressure at sea or ocean level.
For example the boiling temperature of water is 100 degree celcius.
Thus, each mixture decrease the boiling point of the water, option "A" is correct.
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Which is one way scientist communicate the results of an experiment?
Answer:
By writing an experiment report
Explanation:
What is the lowest value of n that allows g orbital to exit
Answer in the correct significant figures: 35.6 + 56.27 *
Answer:
101.87
Explanation:
that's the answer
A white rhinoceros weighs about 1,500 pounds (lb). How many tons (T) does the rhinoceros weigh? (1 T =
A. 1.5 T
o
B. 1 T
C. 0.75 T
D. 0.5 T
Answer:
C
Explanation:
1 lb is 0.0005 T. So if you can do the math, (1500x.0005) it comes out to 0.75 T.
Abigail obtained 18.9 grams of calcium carbonate after performing a reaction. From her calculations, she knew she should have obtained 9.9 grams. What was her percent error? Round your answer to one place behind the decimal. Do not include the unit.
Answer:Percent error= 90.9%
Explanation:
Percent error or percentage error is defined as the percentage of the difference between a measured value usually from an experiment and an exact value in comparison to the exact number.
its formula is thus
Percent error = experimental value - exact or actual value /exact value x 100
=(18.9 - 9.9 /9.9 ) x 100= 9/9.9) x 100
0.909 x 100 = 90.90 = 90.9%
According to Dalton, the pressure of a mix of gases in a single container is the sum of all of the pressures of the individual gases: Ptotal = Pa + Pb + … If a 20.0L container at 30°C has 3.4 atm of methane and 1.68 atm of ethane, what is the total pressure of the container?
Answer:
The correct answer is 5.08 atm
Explanation:
This question tests our knowledge of the Dalton's law of partial pressures which is stated in the question; that the pressure of a mixture of non-reacting gases in a single container is the sum of all the pressures of the individual gases.
It can hence be represented mathematically as Ptotal = Pa + Pb + ...
Ptotal = pressure of methane + pressure of ethane
Ptotal = 3.4 atm + 1.68 atm
Ptotal = 5.08 atm
Sodium hydroxide and water will react at room temperature. What does this indicate about its activation energy? A. The activation energy is very low. B. The activation energy is at exactly 600 kJ. C. The activation energy is very high. D. The reaction cannot reach activation energy.
Answer:
The answer would be C.
Explanation:
I took a test with the same question.
The activation energy is very high. Hence, option C is correct.
What is activation energy?Activation energy is the sufficient amount of energy necessary to initiate a chemical reaction.
When sodium hydroxide (NaOH) dissolves in water, it is distributed into positively-charged sodium ions and negatively - charged hydroxide ions.
These cations and anions move around in the water, free and independent of each other, though cations tend to be surrounded more closely by anions and vice versa.
Hence, when sodium hydroxide and water will react at room temperature, the activation energy is very high.
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explain using diagrams how potassium forms the compound potassium flouride when it reacts with flourine
Answer:
The answer to your question is given below.
Explanation:
Potassium (K) has 19 electrons with electronic configuration of 2, 8, 8, 1.
Fluorine (F) has 9 electrons with electronic configuration of 2, 7.
Fluorine needs 1 electron to complete it's octet configuration.
Hence, potassium (K), will lose 1 electron to fluorine (F) to form potassium ion (K+) with electronic configuration of 2, 8, 8. The fluorine atom (F) will receive the 1 electron from potassium to form the fluoride ion (F-) with electronic configuration of 2, 8.
**** Please see attached photo for further details.
Atoms contain positive and negative charges. Why is the overall charge on an atom neutral?
A. Atoms contain the same amount of protons and electrons, and their charges cancel out.
B. The nucleus of an atom contains neutrons, which keep the positive and negative charges balanced.
C. Atoms are all negatively charged because electrons are on the outside of the atom.
D. Atoms contain the same amount protons and neutrons, and their charges cancel out.
Answer:
Atoms contain the same amount protons and neutrons, and their charges cancel out.
Explanation:
Answer via Educere/ Founder's Education
Atoms contain positive and negative charges, the overall charge on an atom neutral because Atoms contain the same amount of protons and electrons, and their charges cancel out.Hence, Option (A) is correct
What is an Atom ?
An atom is the smallest unit of ordinary matter that forms a chemical element.
Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms.
Atoms are extremely small, typically around 100 picometers across.
An atom consists of a positively charged nucleus, surrounded by one or more negatively charged particles called electrons.
The positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral.Hence, Option (A) is correct
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If you run a particular reaction, and in theory it was supposed to yield 50.0 grams of product, and the percent yield is 75%, how many grams did you actually end up with?
Answer:
37.5 grams
Explanation:
The percent yield shows how much of the reactant have been converted to product. The percent yield is the ratio of actual yield to theoretical yield multiplied by 100%. It is given by the formula:
%yield = Actual yield/ theoretical yield × 100%
Given that theoretical yield = 50 grams and the percent yield is 75%.
Using the formula and substituting:
75% = Actual yield/ 50 g × 100%
75% / 100% = Actual yield / 50 g
0.75 = Actual yield / 50 g
Actual yield = 0.75 × 50 g
Actual yield = 37.5 grams
Give two examples of neutralization
Answer:examples for neutralization - treating indigestion,treatment for insect bites.hope it help you
Explanation:
5. What distinguishes the noble gases from other elements in the main group?
How does this contribute to the tendency for the various elements to react
with each other?
Answer:
Noble gases are the least reactive of all known elements. Their outer energy levels are full because they each have eight valence electrons. ... As a result, noble gases cannot become more stable by reacting with other elements and gaining or losing valence electrons.
Explanation:
Noble gases have complete valence shells so they do not participate in the reactions while the other elements in the main group have incomplete valence shells so they participate in the reaction to complete it.
What are noble gases?Noble gases can be described as the six elements that belong to the 18th group of the modern periodic table. The elements of group 18 are Helium, Neon, Argon, Krypton, Xenon, and Radon.
Under normal temperature and pressure conditions, all noble gases exist in the gaseous state and exhibit low chemical reactivity hence they are also referred to as inert gas. All noble gases possess stable electronic configurations because their valence shell is fully filled.
Noble gases are generally found as mono-atomic gases. The general electronic configuration group 18 elements can be written as ‘ns²np⁶’ where n is the principal quantum number.
Therefore, the reactivity of the noble gases can be distinguished from other elements in the main group.
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which of the following compounds is carbon tetrafluoride
Answer: CF4 is the formula
Explanation:
Answer:
CH4
Explanation:
This answer is for APEX
(30 points) alright so there’s this girl I’m ab to slide in her dms I just need a pickup line but nothing inappropriate bc I don’t like to slide in thirsty so if anyone has a completely hydrated cute pickup line help a simp out
Answer:
Are you a fruit, because honeydew you know how beautiful you look right now?
or maybe
I hear you’re good at algebra…..Will you replace my eX without asking Y?
or maybe
On a scale of one to ten you’re a nine… Because I’m the one left that you need.
Explanation:
Hope these help you.
please help :) How can scientists ensure that their data are reliable? A) by making a single observation B) by recording values without units C) by keeping the results private D) by repeating trials during an experiment
Answer:
D. by repeating trials during an experiment
Explanation:
chile its actually d
Explanation:
How many gram of zinc will have to be treated with dilute hydrochloric acid to liberate 1.85 dm³ of hydrogen at 27°C and 750mmHg?
Answer:
Explanation:
given
volume=1.85 d m^3
T=27 degree C=27+273 k=300 k
P=750 mmHg
mass of zinc=?
we know that PV=nRT
n=m/M
PV=mRT/M
M for zinc=65.4
PVM=mRT
m=PVM/RT
m=750*1.85*65.4/0.0821*300
m=90742.5/24.63
m=3684
hope this will help u
HELP PLEASE NAME THESE COMPOUNDS topic of amines and amides please explain you steps so i can do the rest of the problems myself
The attachment shows the diagram of two molecules respectively;
The first molecule in the attachment is known as triethylamine,The functional group is amine Which is - CONH2
And there is a methyl group as an attachment, attached at the third(3) carbon atom,making the compound triethyamine.
The second molecule in the attachment is an example of a secondary amide.
The longest carbon chain is five which pentanamide.
The functional group is amide.
The compoud is named by replacing the suffix - ane in pentane (alkane) to the suffix - amide.
Making the compound pentanamide.
PLS HELP ASAP 15 POINTS TYSM which of the following is a consequence of urban heat islands? a) increased precipitation downwind of the city b) increased winds within the city c) increased precipitation upwind of the city d) decreased winds within the city
Answer:
Hey!
Your answer is definitely A!
Explanation:
Hope this helps!
:>
In an ecosystem, the following is a consequence of urban heat islands which is increased precipitation downwind of the city.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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How many grams of silver will be produced if 86g of copper are used
The substances are placed in separate containers at room temperature, and each container is gradually cooled. Which of these substances will solidify before the temperature reaches 0°C? benzene water butane nitrogen
Answer:
Benzene
Explanation:
You have to find the freezing point for each of these (make sure they're in Celsius). You might want to double check these but:
Benzene: 5.5
Water: 0
Butane: -138
Nitrogen: -210
The substances that will solidify before the temperature reaches 0°C is benzene. The correct option is A.
What is freezing point?Freezing, also known as solidification, is a phase transition that occurs when the temperature of a liquid falls below its freezing point.
If the intermolecular forces between its molecules are strong, the freezing point is high.
When the forces are weak, the freezing point is low. The freezing point of a liquid or the melting point of a solid occurs when the solid and liquid phases are in equilibrium.
Pure benzene has a freezing point of 5.48 degrees Celsius. Because of the salt in it, fresh water freezes at 32 degrees Fahrenheit, but seawater freezes at around 28.4 degrees Fahrenheit.
Thus, as per the given scenario, the correct option is A.
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when an atom gains an electron,what charge does the ion have
Answer:
if an atom gains an electron, the ion has negetive charge
In 1838 botanist Matthias Schleiden determined that all plants are composed of cells. In 1839, anatomist Theodor Schwann proposed that all animals are composed of cells. In 1855, biologist Rudolph Virchow added to Schleiden's and Schwann's observations and proposed that all living things are composed of cells. Which statement is also part of Virchow's cell theory?
Answer:
cells arose from preexisting cells
Explanation:
Rudolph Virchow is a German biologist that built on the work of other scientists such as Theodor Schwan to contribute his own quota to the development of the cell theory as it is currently known.
After several studies, Virchow rejected the idea of spontaneous generation and accepted the initially rejected idea of cell division. He earlier believed that cell division only takes place is some special type of cells and not in all cells.
Even though Virchow was not the first to bring the idea of cells arising from preexisting cells, he was the one that popularized the idea and added it to the earlier belief that all living organisms are made up of cells.
Answer:
B
Explanation:
The primary function of a scuba regulator is to: Reduce high-pressure gas in the scuba cylinder to a more breathable intermediate pressure. Reduce high-pressure gas in the scuba cylinder to ambient (surrounding) pressure. Provide a diver with a continuous flow of oxygenated air. None of the above.
Answer:
Reduce high-pressure gas in the scuba cylinder to ambient (surrounding) pressure.
Explanation:
The primary function of a scuba regulator would be to reduce high-pressure gas in the scuba cylinder to ambient pressure.
A scuba regulator is a structure found attached to the scuba cylinder usually carried by scuba divers. The structure regulates the pressure of the breathing gas in the cylinder to a safe level before the gas becomes available for the breathing process of divers.
Usually, the gas in a scuba cylinder is at a high level. Hence, what the regulator does is to bring it down to a level that would be safe for the breathing of the diver.
in the symbol 3p4
a. the 3 represents the principal energy level
b. the p represents the principal energy level
c. the 4 represents the principal energy level
d. all of the above
help!
Answer:
a. the 3 represents the principal energy level
Explanation:
3 is the principal energy level. The p is the sublevel. 4 is the possible occupying electron.
Which Nobel gas electron structures do the atoms in a
molecule of hydrogen chloride attain?
And can you tell me why aswell please?
Answer:
The noble as structures attained are helium and argon
Explanation:
The electron configuration of chlorine atom is 1s²2s²2p⁶3s²3p⁵
The elecron configuation of hydrogen is 1s¹
The electron configuration of argon atom is 1s²2s²2p⁶3s²3p⁶
The elecron configuation of helium gas is 1s²
Therefore, in the hydrogen chloride molecule the hydrogen and the chlorine each share one electron from the other atom to attain the the stable noble gas structure of helium for hydrogen and argon for chlorine.
Which of these is true about electrons? posses a positive electrical charge of one (+1) have a negative electrical charge of one (-1) indicates the number of protons in each atom equals the sum of protons plus neutrons in each atom
Answer:
have a negative electrical charge of one (-1)
Explanatio
Electrons have an electrical charge of negative one. When you think electron, always think -1
For the set of ionic compounds, LiCl, AgCl, PbCl2, choose the correct characterization of their solubilities in water from the response list. Group of answer choices All three salts are soluble. None of the three salts are soluble. Two of the three salts are soluble. One of the three salts is soluble.
Answer:
Two of the three salts are soluble.
One of the three salts is soluble.
Explanation:
One or two of the three salts would be soluble in water depending on if the water is cold or hot.
According to the solubility rules of chloride salts, all chlorides are soluble in cold water except for those of silver (Ag), lead (Pb), and mercury (I) (Hg).
This thus means that both AgCl and [tex]PbCl_2[/tex] would be insoluble in cold water while LiCl would be soluble.
[tex]PbCl_2[/tex] is, however soluble in hot water.
Hence, in cold water, one of the three salts (LiCl) would be soluble, while in hot water, two of the three salts (LiCl and [tex]PbCl_2[/tex]) would be soluble.
Increasing temperature can
