what is the state of the substance at room temperature (20°c)
Answer:
dez nuts. the forth quauter in ur girls buttr
Gas is well separated with no regular arrangement, liquids are close together and solids are tightly packed. Solid, liquid, and Gas are the state of substances at room temperature.
What is the state of substance?There are three state of substances:
solidLiquidGasThe chair you are sitting on is a solid, the water you drink is liquid, and the air you breathe is a gas. The atoms and molecules don't change, but the way they move about does. Water, for example, is always made up of two hydrogen atoms and one oxygen atom.
Physical properties of a particular substance determine its state at room temperature. If both its normal melting point and its normal boiling point are below room temperature (20°C), the substance is a gas under normal conditions.
Oxygen is a gas at room temperature. If the normal melting point of a substance is below room temperature, the substance is a liquid at room temperature.
If both the normal melting point and the normal boiling point are above room temperature, the substance is a solid.
Therefore, solid, liquid and gas all exist as substances at room temperature.
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You heat 51 grams of magnesium over a Bunsen burner for several minutes until it reacts with oxygen in the air. Then you weigh the resulting product and see that it is now 53 grams. How does this happen without breaking the Law of Conservation of Mass?
Answer:
The mass was there all along, it was just in the air. The weight of the oxygen from the air is not weighed in the beginning, only at the end as part of the product, making it seem like there is a total mass change.
Cuci
what is the formula?
Answer:
Copper(I) chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid. Impure samples appear green due to the presence of copper(II) chloride.
Explanation:
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A laser pointer used in the classroom emits light at 5650 Å, at a power of 4.00 mW. (One watt is the SI unit of power, the measure of energy per unit of time. 1 W = 1 J/s). How many photons are emitted from the pointer in 115 seconds?
Answer:
n = 1.3 x 10¹⁸ photons
Explanation:
First we need to calculate the amount of energy released in given time:
E = Pt
where,
E = Energy = ?
P = Power = 4 mW = 0.004 W
t = time = 115 s
Therefore,
E = (0.004 W)(115 s)
E = 0.46 J
Now, this energy can be given in forms of photons as:
E = nhc/λ
where,
n = No. of photons = ?
h = Plank's Constant = 6.626 x 10⁻³⁴ J.s
c = speed of light = 3 x 10⁸ m/s
λ = wavelength of light = 5650 x 10⁻¹⁰ m
Therefore,
0.46 J = n(6.626 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(5650 x 10⁻¹⁰ m)
n = (0.46 J)/(3.5 x 10⁻¹⁹ J)
n = 1.3 x 10¹⁸ photons
Answer:
1.308 x 10¹⁸ photons were emitted from the laser pointer.
Explanation:
Given;
wavelength of the photon, λ = 5650 Å = 5650 x 10⁻¹⁰ m
power emitted by the source, P = 4 mW = 4 x 10⁻³ W
time of photon emission, t = 115 s
The energy of a single photon is given by;
E = hf
f = c / λ
[tex]E = \frac{h c }{\lambda}[/tex]
where;
c is speed of light = 3 x 10⁸ m/s
h is Planck's constant = 6.626 x 10⁻³⁴ Js
[tex]E = \frac{(6.626 *10^{-34}) (3*10^8) }{5650*10^{-10}}\\\\ E = 3.518*10^{-19} \ J[/tex]
Energy of the source (laser pointer) = P x t
= (4 x 10⁻³ W) (115 s )
= 0.46 J
If no energy is lost, then emitted energy by the source must be equal to total energy of then photons;
[tex]E_T = n E_{photon}\\\\n = \frac{E_T}{E_{photon}}\\\\n = \frac{0.46}{3.518*10^{-19}}\\\\n = 1.308*10^{18} \ photons[/tex]
Therefore, 1.308 x 10¹⁸ photons were emitted from the laser pointer.
The formula for a compound containing sodium and oxide ions would contain... This
compound would have an overall ... charge.
Answer:
Explanation:
the formula of the compound containing sodium and oxide ion is
NaOH the charge on sodium is partial positive and the charge on hydroxide ion is partial negative
another compound containing sodium and oxide ion is Na2O here the charge on sodium oxide is neutral
A substance made up of one type of atom is called an(a) ______________.
A. element
B. compound
C. atom
A substance that cannot be converted into another substance is known as an element. Each type of atom that makes up an element is unique. The correct option is A.
A substance whose atoms all contain the same number of protons is said to constitute an element; alternatively, all the atoms of a certain element must contain the same number of protons. Chemical reactions cannot degrade elements since they are the simplest chemical forms.
A compound is created when two or more components join chemically in a predetermined mass ratio.
Thus the correct option is A.
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When 3.0 g of water is warmed from 10.0∘C to 80.0∘C, how much heat energy is needed? Specific heat for water is 4.186Jg(∘C).
Answer:
Specific heat is the amount of heat energy required to raise the temperature of substance by, the units for specific heat is, each element have particular fixed specific heat.
The heat energy change can be obtained by the formula

Temperature change can be represented by 

If we know the specific heat of substance then we can easily calculate the heat energy change of the substance
The compound 2-hydroxybiphenyl (o-phenylphenol) boils at 286 °C under 101.325 kPa and at 145 °C under a reduced pressure of
14 Torr. Calculate the value of the molar enthalpy of vaporization. Compare this value to that given in the CRC Handbook.
Answer: [tex]\Delta H_{vap}[/tex] = 55.1 kJ/mol
Explanation: Molar Enthalpy of Vaporization([tex]\Delta H_{vap}[/tex] ) is the energy needed to change 1 mol of a substance from liquid to gas at constant temperature and pressure.
For the 2-hydroxybiphenyl, there two temperatures and 2 pressures. In this case, use Clausius-Clapeyron equation:
[tex]ln\frac{P_{2}}{P_{1}}=\frac{\Delta H_{vap}}{R} (\frac{1}{T_{1}}-\frac{1}{T_{2}} )[/tex]
[tex]\Delta H_{vap}[/tex] is in J/mol:
1) Temperature in K
[tex]T_{1}=[/tex] 286 +273 = 559K
[tex]T_{2}[/tex] = 145 + 273 = 418K
2) Both pressure in Pa
[tex]P_{1}[/tex] = 101325Pa
[tex]P_{2}[/tex] = 14*133 = 1862Pa
Since molar enthalpy is in Joules, gas constant R is 8.3145J/mol.K
Replacing into the equation:
[tex]ln\frac{1862}{101325}}=\frac{\Delta H_{vap}}{8.3145} (\frac{1}{559}-\frac{1}{418} )[/tex]
[tex]ln(0.0184)=\frac{\Delta H_{vap}}{8.3145} (\frac{141}{233662} )[/tex]
[tex]\Delta H_{vap}=\frac{-3.9954*1942782.7}{-141}[/tex]
[tex]\Delta H_{vap}=55051.02[/tex]
[tex]\Delta H_{vap}=55051.02[/tex]
[tex]\Delta H_{vap}=55.1[/tex] kJ/mol
Using those values, molar enthalpy is 55.1 kJ/mol
Comparing to the CRC Handbook, which is [tex]\Delta H_{vap}=71[/tex] kJ/mol:
[tex]\frac{55.1}{71}[/tex] = 0.78
The calculated value is 0.78 times less than the CRC Handbook.
Which statement best describes chemical properties of matter? Chemical properties, such as density, must be observed when a substance is in its natural state at room temperature and normal atmospheric pressure. Chemical properties, such as reactivity, must be observed when a substance is in its natural state at room temperature and normal atmospheric pressure. Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form. Chemical properties, such as boiling point, are generally observed as the identity of a substance changes and one or more new substances form.
Answer:
Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form.
Explanation:
Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form. Hence, option C is correct.
What are the chemical properties of matter?Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter.
Substances made of wood, such as paper and cardboard, are also flammable.
Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter.
They include reactivity, flammability, and the ability to rust.
Hence, option C is correct.
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The nutrition label on rice lists the amounts of proteins, carbohydrates, and fats in one serving. These substances are important for human nutrition. How are proteins, carbohydrates, and fats related to the discipline of chemistry?
Answer:All are chemical compounds.
How are the Celsius, Kelvin, and Fahrenheit scales similar? How are they different?
celcius and Fahrenheit are the same at -40 degrees since the scales converge . celcius and Kelvin become Equal at high temperatures as the difference. of 273. 15 between them gets lost in the noise . 0 degree Celsius is Equal to 32degrees Fahrenheit.
To what volume (in mL) would you need to dilute 25.0mL of a 1.45 m solution of Kcl to make a 0.0245m solution of KCl
Answer:
The answer is
1479.60 mLExplanation:
In order to calculate the volume needed we use the formula
[tex]V_2 = \frac{C_1V_1}{C_2} [/tex]
where
C1 is the concentration of the stock solution
V1 is the volume of the stock solution
C2 is the concentration of the diluted solution
V2 is the volume of thevdiluted solution
From the question
C1 = 1.45 M
V1 = 25 mL
C2 = 0.0245 M
So we have
[tex]V_2 = \frac{1.45 \times 25}{0.0245} = \frac{36.25}{0.0245} \\ = 1479.59...[/tex]
We have the final answer as
1479.60 mLHope this helps you
A average marathon runner run the 26.1 miles in 4 hrs 30 minutes. What is the runners average pace in miles/minutes.
Explanation:
4hr 30 m = 270 min
270/ 26.1 = 10. 34
1 mile per 10.34 mins
What is Avogadro's number?
the number of atoms in exactly 14.00 g of carbon-12
the number of atoms in a kilogram of any substance
the number of atoms, molecules, ions, formula units, or other particles in a mole of a substance
the number of atoms, molecules, ions, formula units, or other particles in a gram of a substance
Answer:
C
Explanation:
its not A since its actually the atoms in exactly 12g of crabon-12
-not B since its grams not kilograms
-not D since it says "gram" which would mean that we measure the particles in a gram instead of a mole
Avogadro's number is the number of atoms, molecules, ions, formula units, or other particles in a mole of a substance. Therefore, option (c) is correct.
What is Avogadro's number?The Avogadro constant commonly denoted [tex]N_A[/tex] is the proportionality factor that the number of constituent particles such as molecules, atoms, or ions in one mole of a sample.
Avogadro's number is a constant with an exact value of 6.022 × 10²³ reciprocal moles. Avogadro's number is named by Stanislao Cannizzaro after the Italian scientist Amedeo Avogadro, who explained it four years after Avogadro's death.
The numerical value of the Avogadro constant is in reciprocal moles, a dimensionless number known as the Avogadro number. The value of the Avogadro constant, the mass of one mole of a chemical compound, in grams.
It is numerically equal to the average mass of one molecule of the compound in daltons. One dalton is 1/12 of the mass of one carbon-12 atom, which is the mass of one nucleon.
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boling water is considered as
Answer:Boiling water is a physical change, as it rearranges molecules but does not affect the internal structures. Boiling water forces the water molecules away from each other as the liquid changes to vapor. In a chemical change, new chemical substances are created or formed. Advertisement. Physical changes affect the state of an item, and a chemical change happens at a molecular level.
Explanation:
hope it helps:))
Answer:
gragsgv
Explanation:
cwnbcsjhbvcd
Draw the conjugate base for the acid (CH3)2C=OH+ Remember to include charges and non-bonding electrons where
necessary
Answer:
Explanation:
An acid is a substance that, when dissolved in water produces hydrogen ions, H⁺ as the only positive ion. e.g.
HCl ↔ H⁺ + Cl⁻
HNO₃ ↔ H⁺ + NO⁻₃
This process is known as ionization. The characteristics properties of an acid in solution are due to the presence of these hydrogen ions. In these reactions, the negative ions formed or sometimes the neutral compounds are usually known as the conjugate base of such acid.
From the given information, the conjugate base of the acid given can be seen in the attached image below.
The conjugate base for the acid is attached below.
What is an Acid?An acid is a substance that, when dissolved in water produces hydrogen ions, H⁺ as the only positive ion. e.g.
HCl ↔ H⁺ + Cl⁻
HNO₃ ↔ H⁺ + NO⁻₃
This process is known as ionization. The characteristics properties of an acid in solution are due to the presence of these hydrogen ions. In these reactions, the negative ions formed or sometimes the neutral compounds are usually known as the conjugate base of such acid.
The conjugate base of the acid given can be seen in the attached image below.
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What is the mass, in grams, of 1.33 mol of water, H2O?
Answer:
24.0g H2O
Explanation:
1.33 mol (18.016g/1 mol) = 24.0g H2O
what ahppens when you free lava?
Answer:
It will melt everything and if lava goes into water it will become rock.
Hope this helped you!
Explanation:
indigestion tablets neutralise acid in the stomach. what does this tell you about indigestion tablets?
Answer:
It is basic.
Explanation:
Bases can neutralize acids.
which of the following best describes a non metal
Answer:
-a nonmetal is a substance that lacks the characteristics of a metal.
-Seventeen elements are generally classified as nonmetals: most are gases (hydrogen, helium, nitrogen, oxygen, fluorine, neon, chlorine, argon, krypton, xenon and radon); one is a liquid (bromine); and a few are solids (carbon, phosphorus, sulfur, selenium, and iodine).
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Scientists in a particular fieScientists in a particular field strive for the same quality of work because they know their peers will be reviewing their scientific claims. What does this review process help ensure?
standards of the profession
publication in scientific journals
resistance to new information
access to university databases
What mass of neon gas is required to fill a 5.00-L container to
a pressure of 1.02 atm at 25 °C?
Answer:
[tex]m=4.21g[/tex]
Explanation:
Hello,
In this case, by using the ideal gas equation:
[tex]PV=nRT[/tex]
We can compute the mass of neon gas at the given conditions by firstly computing the moles and also considering the temperature in kelvins (298K):
[tex]n=\frac{PV}{RT}=\frac{1.02atm*5.00L}{0.082\frac{atm*L}{mol*K}*298K}\\ \\n=0.209mol[/tex]
Finally, by using the atomic mass of neon gas (20.18g/mol) we compute the required mass to fill the 5.00-L container:
[tex]m=0.209mol*\frac{20.18g}{1mol}\\ \\m=4.21g[/tex]
Best regards.
The mass of neon gas will be "4.21 g".
Ideal Gas Equation:Given:
Pressure, P = 1.02 atmVolume, V = 5.00 LTemperature, T = 25°C or 298 KBy using Ideal Gas Equation,
⇒ [tex]PV = nRT[/tex]
or,
⇒ [tex]n = \frac{PV}{RT}[/tex]
By substituting the values,
[tex]= \frac{1.02\times 5.00}{0.082\times 298}[/tex]
[tex]= 0.209 \ mol[/tex]
hence,
The Mass will be:
= [tex]0.209\times \frac{20.18}{1}[/tex]
= [tex]4.21 \ g[/tex]
Thus the above answer is right.
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What is the use of density in the calculation of percentage by mass?
Answer:
First, the direct method requires recording the total mass of solution, and then evaporating off the solvent. The solid left behind is the solute, which is then weighed and used to calculate mass percent. Density can also be used to determine the mass percent of an unknown concentration.
in my opinion:)
3.0 moles of nitrogen is reacted with 11.0 moles of hydrogen to produce ammonia according to the chemical equation shown below. Which one of the following statements is false?
N2(g) + 3 H2(g) → 2 NH3(g)
a. Hydrogen is the excess reactant.
b. 2.0 moles of hydrogen are left over.
c. 12.0 moles of ammonia are produced.
d. Nitrogen is the limiting reactant.
Answer:
c
Explanation:
From the equation, we can say that we need thrice the number of hydrogen than that of nitrogen
we are given 3 moles of nitrogen and 11 moles of hydrogen
but thrice the number of moles of nitrogen is 9, hence we have hydrogen in excess or Hydrogen is the excess reagent
Since we had 11 moles of Hydrogen and we only needed 9, 2 moles of hydrogen are left over
From the equation, we can see that the moles of ammonia formed will be twice the moles of nitrogen
Since 3 moles of nitrogen are used, the reaction will give us 6 moles of Ammonia and NOT 12 moles, therefore c is the correct answer
Since we have hydrogen in excess, our reaction is being limited because we have less Nitrogen, Hence Nitrogen is the Limiting Reagent
Option C is the only false statement
The false statement is that "12.0 moles of ammonia are produced"
According to the equation of reaction:
N₂ + 3H₂ >>>>> 2NH₃
1 mole of N₂ reacts with 3 moles of H₂
3 moles of N₂ will react with 9 moles of H₂
Since 3 moles of N₂ is said to react with 11 moles of H₂ (instead of 9 moles of H₂), H₂ is in excess by 2 moles. That is, N₂ is the limiting reactant.
Since N₂ is the limiting reactant:
1 mole of N₂ produces 2 moles of NH₃
3 moles of N₂ will produce 6 moles of NH₃
Therefore, we can conclude that:
Hydrogen is the excess reactant2.0 moles of hydrogen are left overNitrogen is the limiting reactantLearn more here: https://brainly.com/question/19555927
Which of the following changes lead to a decrease in entropy?
a. mixing of pure gases
b. sugar dissolving in coffee
c. melting snow
d. the sublimation (vaporization) of dry ice (solid carbon dioxide)
e. halving the volume of a gas
Answer:
halving the volume of a gas
Explanation:
Entropy refers to the degree of disorderliness of a system. The greater the volume of a gas, the greater its entropy. The entropy of a system is directly proportional to its volume.
Hence a decrease in the volume of a gas leads to a decrease in its entropy. Ultimately, if the volume of a given mass of gas is halved, its entropy decreases according.
An atomic model shows 19 protons, 20 neutrons, and 19 electrons. What is the mass number of the atom?
2. You are tasked with calculating the average weight of kindergartners in a class of
21 students. Their weights range from a low of 40.5 lbs to a high of 58.6 lbs.
How many significant figures should be in the average that you find?
How many sig figs are in 340.0 mL
Answer:
4
Explanation:
there is a decimal place present. so you would take away any zeros before the number.
Answer:
4 i think
Explanation:
Explain why some people use the term decimal system as a synonym for the metric system?
Answer:
The term Decimal is coined from the word Decimus. Decimus is a Latin word which means ‘tenth’.
The Decimal system is a system of numbering that is based on multiples of tens. It is flexible and easy to convert from one metric to another.
The preference of the term over the Metric System is because the word Metric is related more to the measurement of lengths if we looked at the origin of the word which is French.
Cheers!
wich element is likely to be the most reactive? bromine (Br) chlorine (Cl) fluorine (F) iodine (I)
most reactive among them is fluorine because it is the most electronegative element
Answer:
fluorine (F)
Explanation:
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