Answer:
Explanation:
percent yield is ratio of actual yield or experimental yield divided by theoretical yield multiplied by 100 .
percent yield of 93.4 % means , the actual yield is 93.4 % what was expected from the reaction on the basis of given chemical reaction .
If in the experimental process , some sodium hydrogen carbonate is left unreacted due to absence of reactant HCl which is also required to obtain product , the percent yield will be increased if the required HCl is also provided .
Hence the percent yield will be increased if required HCl is made available .
Given isotope of nitrogen (N) contains 7 electrons, 7 protons and 8 neutrons. - What is the mass number - What is its atomic number
Answer:
Mass no= 16
and atomic no= 7
Explanation:
mass number is equals to number of protons + number of neutrons .
atomic number is equals to number of protons .
HELP ME OUT PLZ Today is the deadline
Answer:
Option (1)
Explanation:
When two or more substances are chemically combined in a fixed proportion of mass, substance formed is a compound.
Properties of a compound are different from the properties of the elements from which the compound is formed.
If Magnesium (Mg) is burned in the presence of Oxygen (O₂), Magnesium oxide (MgO) is formed.
Properties of MgO are different from Mg and O₂ because MgO is a COMPOUND.
Option (1) will be the answer.
example of nobel gas
Answer:
helium , krypton,xenon,radon, argon are noble gasses
The mass number of a chromium atom is 52 and it has 24 protons. How many neutrons does this atom have? 24 28 76 80
The number of protons and neutrons together makes the total atomic mass of the element. The atom of chromium has 28 neutrons. Thus, option b is correct.
What is an atomic mass?An atomic mass is the property of an element that defines the number of protons and neutrons of the atom placed in a periodic table. The atomic mass is represented at the lower half of the atomic symbol.
The atomic mass is the sum of the neutrons and the protons that are held together in the nucleus of the atom as a concentrated mass. The atomic number is given as,
Atomic number = number of protons + number of neutrons
Given,
The atomic mass of chromium = 52
Number of protons = 24
Substituting values above:
52 = 24 + number of neutrons
number of neutrons = 52-24
= 28
Therefore, the number of neutrons of a chromium atom is 28.
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Answer: option b, 28
Explain this
When a small piece of glowing sodium is placed inside a gas jar filled with chlorine gas, the sodium continues to burn brightly but when the gas is replaced by argon gas, the glowing sodium becomes extinguished.
Answer:
Because Argon is a inert gas
Explanation:
Inert gases don't take place in any experiments
Answer:
Below.
Explanation:
The sodium reacts strongly with the chlorine to form NaCl and the heat of reaction continues the brightness, whereas it does not react with the inert gas argon and soon cools down.
If the pH of a weak acid solution is 2.500 and the solution has a concentration of 0.100M, what is the Ka of the weak acid HA?
Answer:
The Kₐ of the weak acid is 1.033×10⁻⁴
Explanation:
The dissociation of a weak acid in aqueous solution is limited to about 5 to 10%
The acid dissociation reaction is given as follows;
HA (aq) + H₂O (l) → H₃O⁺(aq) + A⁻ (aq)
Given that the pH = 2.5, we have
pH = -log₁₀[H₃O⁺] = 2.5
∴ [H₃O⁺] = 10^(-2.5) = 0.0031623
[tex]K_a = \dfrac{[H_3O^+][A^-]}{[HA]}[/tex]
Kₐ = [H₃O⁺][A⁻]/[HA] = (0.0031623^2)/(0.1 - 0.0031623) = 1.033×10⁻⁴
The acid dissociation constant, Kₐ for weak acid is very low as obtained
PLEASE HELP ASAP The molecular weight of oxygen gas (O2) is 32 g/mol. What is the mass of a single oxygen atom? 2.66 x 10-23 g 3.13 x 10-1 g 1.06 x 10-23 g 5.31 x 10-23 g
Answer:
5.31×10¯²³ g.
Explanation:
Data obtained from the question include:
Molar weight of O2 = 32 g/mol
Mass of 1 oxygen atom =..?
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms.
This implies that 1 mole of O2 also contains 6.02×10²³ atoms.
1 mole of O2 = 32 g
The mass of 1 atom of O2 can be obtained as follow:
32 g of O2 contains 6.02×10²³ atoms.
Therefore Xg of O2 will contain 1 atom i.e
Xg of O2 = 32/6.02×10²³
Xg of O2 = 5.31×10¯²³ g
Therefore, the mass of a single oxygen atom is 5.31×10¯²³ g.
The mass of a single oxygen atom is 5.31 x 10⁻²³ grams. Therefore, option D is correct.
The molecular weight of oxygen gas is 32 g/mol. To find the mass of a single oxygen atom, divide the molecular weight by Avogadro's number (6.022 x 10²³ atoms/mol).
Avogadro's number (6.022 x 10²³) represents the number of particles (atoms, molecules, or ions) in one mole of a substance.
To find the mass of a single oxygen atom, divide the molecular weight of oxygen gas by Avogadro's number:
Mass of a single oxygen atom = (32 g/mol) / (6.022 x 10²³ atoms/mol)
Simplifying the expression:
Mass of a single oxygen atom = 5.31 x 10⁻²³ g
Therefore, the mass of a single oxygen atom is 5.31 x 10⁻²³ grams.
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The figure shows a graph of Allison’s walk to school. She follows the black vectors to get to her school. Which if the following best describes her walk?
Answer:
Allison walks 5 blocks west and 3 blocks south.
Explanation:
Vectors have both magnitude and direction. The attached figure shows the graph of Allison’s walk to school. She follows the black vectors to get to her school.
The first vector on the horizontal axis points towards west and there are 5 blocks. Initially, she walks 5 blocks in west direction.
The second vector points in the negative vertical axis. It means that she walks 3 block in south direction.
Hence, the correct option is (D) i.e. Allison walks 5 blocks west and 3 blocks south.
A large scuba tank with a volume of 18 L is rated for a pressure of 220 bar. The tank is filled at 20 °C and contains enough air to supply 1860 L of air to a diver at a pressure of 2.37 atm (a depth of 45 feet). Was the tank filled to capacity at 20 °C?
Answer:
Yes, at 20 °C the tank was filled to full capacity
Explanation:
Given;
let initial pressure, P₁ = 2.37 atm
let initial volume, V₁ = 1860 L
let final pressure, P₂ = 220 bar = 217.123 atm
let final volume, V₂ = ?
Subject the air volume (1860 L ) at 2.37 atm to the tank rating (220 bar)
Ideal law is given by;
PV = nRT
At a fixed mole and gas temperature, the equation becomes;
P₁V₁ = P₂V₂
V₂ = (P₁V₁) / P₂
V₂ = (2.37 x 1860) / 217.123
V₂ = 20.3 L
After subjecting the air volume to tank rating, the volume of the air at 220 bar is 20.3 L which is greater than tank volume (18 L).
The extra 2.3 L can be assumed to be compressed gas volume due to the given (lower) temperature.
Thus, at 20 °C the tank was filled to full capacity.
The standard reduction potential of a chromium electrode is -0.74 volts when chromium is reduced from chromium (III). The standard potential of the cell where chromium is oxidized and cerium (IV) is reduced to cerium (III) is 2.35 V. For each half reaction how many electrons are transferred
Answer:
three electrons were transferred in the process
Explanation:
The electrode potential of the cathode is
E°cathode= E°cell + E°anode
E°cathode = 2.35V + (-0.74V)
E°cathode= 1.61 V
Let us look at the reduction half equation; the oxidation half equation must be;
Oxidation half equation;
Cr(s) ----> Cr^3+(aq) + 3e
The reduction half equation must now be
Reduction half equation;
3Ce^4+(aq) + 3e ----> 3Ce^3+(aq)
This implies that three electrons were transferred in the process as shown by the balanced half cell reaction equations.
distinguish between deliquescence and efflorescence.
Explanation:
Deliquescent substances are solids that absorb moisture from the atmosphere until they dissolve in the absorbed water and form solutions. Efflorescent: Efflorescent substances are solids that can undergo spontaneous loss of water from hydrated salts.
Which of the following is represented by the number of significant figures in a quantity? A) estimation B) precision C) accuracy D) scientific notation
Answer: the answer is B estimation
Explanation:
i just took a test
The one that is represented by the number of significant figures in a quantity is scientific notation. The correct option is D.
What is scientific notation?Scientific notation is a method of expressing numbers that are either too large or too small to be written in decimal form.
In the United Kingdom, it is known as scientific form, standard index form, or standard form.
The proper scientific notation format is an x 10b, where an is a number or decimal number with an absolute value greater than or equal to one and less than ten, or 1 |a| 10. b is the power of ten required for scientific notation to be mathematically equivalent to the original number.
Scientific notation is represented by the number of significant figures in a number.
Thus, the correct option is D.
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How are the elements arranged in the modern periodic table?
O A. According to atomic number
B. According to atomic mass
C. According to the number of neutrons
O D. According to the number of electrons
Answer:
A
Explanation:
why the filament of bulb has high melting point
Answer:
The filament of a bulb has a high melting point because of the heat generated inside the bulb.
Explanation:
When electricity is concentrating and run through a bulb, it starts to generate heat. Leave it on long enough and it will start to build up a lot of heat. Have you ever tried touching a light bulb when it has been all day? It's scorching to the skin.
Since electricity generates heat, the bulb's filament has to have a high melting point so it doesn't melt, destroy the bulb, and leave you light-less. If the filament has a high melting point, then it is able to withstand heat generated by electricity and provide you light.
12. Classify the following as conduction, convection or radiation. a. A steel mug kept near a stove becomes hot after some time. b. The metal handlebars of a bicycle are colder than plastic hand grips. c. Some people get sunburn when they go out in the sun for a long time. d. The paper kept above a candle flame starts burning after some time.
A - convection
B - conduction
C - radiation
D - convection
What type of reaction does this equation represent?
2I4O9(s) → 4I2(s) + 9O2(g)
Answer:
2I4O9_4I +9O
Explanation:
Complex compound (
I
4
O
9
) is broken down to form
I
2
and
O
2
Answer:
Decomposition
Explanation:
Because it went from one compound to two elements.
how is impure copper refined by electrolysis
Answer:
By giving electricity to copper compound solution.
Explanation:
Electrolysis is one of the major way of refined copper. The copper containing solution has two electrodes.i) positive electrodes called anode. ii) negative electrodes called cathode. When electricity is pass into the copper containing solution electrolysis process is starts and impure copper is formed in anode and pure copper is formed in cathode.
So, We can get pure copper in cathode through electrolysis.
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Smaller particles in an atom are called ____________.
Answer:
[tex]\large \boxed{\sf subatomic \ particles}[/tex]
Explanation:
The smaller particles in an atom are called subatomic particles. Subatomic particles include electrons, protons, and neutrons.
An atom of an element is shown by the model. A gray circle is surrounded by 4 concentric circles. The innermost circle has gray dots at the north and south positions; the second ring has 8 equally spaced dots, aligning with the inner ring at north and south; the third ring has 14 dots, equally spaced, aligned with the other rings at north and south; the outer ring has dots at north and south. How is this model useful? It shows how electrons are distributed in the shells of an iron atom. It shows how electrons are distributed in the shells of a cobalt atom. It shows how orbitals are distributed in the shells of an iron atom. It shows how orbitals are distributed in the shells of a cobalt atom.
The correct answer is A. It shows how electrons are distributed in the shells of an iron atom.
Explanation:
In the model described, the circles represent the orbitals or shells of the atom, while the dots represent the distribution of electrons (negatively charged sub-particles). Additionally, the description shows the general electronic configuration of this atom is 2, 8, 14, 2, which means in the first orbital there are two electrons, in the second there are eight electrons, in the third, there are fourteenth electrons and in the fifth orbital there are two electrons. This electronic configuration occurs in the atoms of iron. Also, this differs from Cobalt because in cobalt the third orbital has 15 electrons. Thus, the model "shows how electrons are distributed in the shells of an iron atom".
Answer:
a. it shows how electrons are distributed in the shells of an iron atom
Explanation:
edge 2021
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In an experiment, 125ml of H2 is collected over water at 27C and barometric pressure of 753 torr. the vapor pressure of water at 27C is 26.74 what is the partial pressure of H2?
Answer:
Partial pressure of H₂ = 0.9556 atm
Explanation:
Given:
Barometric pressure = 753 torr
Vapor pressure of water = 26.74 torr
FInd:
Partial pressure of H₂
Computation:
Partial pressure of H₂ = Barometric pressure - Vapor pressure of water
Partial pressure of H₂ = 733 - 26.74
Partial pressure of H₂ = 726.26 torr
1 atm = 760 torr
So,
Partial pressure of H₂ = 726.26/760
Partial pressure of H₂ = 0.9556 atm
Which of the outer planets is MOST like Earth? How?
Answer:
venus
Explanation:
hope i helped
brainliest pls pls pls
-Zylynn
Answer: I would say that Saturn is most like Earth. Not only does it have moons, like Earth, but the atmosphere is also denser like Earth. It also has windstorms, granite they are much more intense than Earth’s, but they do indeed happen. Saturn also has hydrogen gas; this gas is here on Earth supporting life in our ocean. Therefore, there is a chance that the conditions on Saturn could provide the essentials for there to be life.
What is the oxidation number of carbon in CO2
Answer: Since oxygen is in group 6 on the periodic table, its valency is
2 −
and hence so is its oxidation number.
But there are 2 oxygen atoms for each carbon atom so the total negative charge due the oxygen is
4 −
But since a molecule must have a net charge of zero in the free form, it implies that the oxidation number of the carbon atom must then be
+ 4
Consider the half reaction below.
Which statement best describes what is taking place?
Chlorine is losing electrons and being oxidized. Chlorine is losing electrons and being reduced. Chlorine is gaining electrons and being oxidized. Chlorine is gaining electrons and being reduced.
Answer:
balancing of charges of both sides
Answer:
A
Explanation:
A...............................
The cell potential of an electrochemical cell is positive. What does that tell
you about the redox reaction?
A. The reduction part of the reaction occurs at the anode.
B. The oxidation part of the reaction occurs at the cathode.
C. The reaction is spontaneous.
O D. The reaction is nonspontaneous.
Answer:
A. The reduction part of the reaction occurs at the anode
Answer:
A
Explanation:
What is meant by 1m length
Answer:
The metre is defined as the length of the path travelled by light in a vacuum in 1/299 792 458 of a second.
Consider a pure crystalline solid that is heated from absolute zero to a temperature above the boiling point of the liquid. Which of the following processes produces the greatest increase in the entropy of the substance?
a) melting the solid
b) heating the liquid
c) heating the gas
d) heating the solid
The question is incomplete, the complete question is;
Consider a pure crystalline solid that is heated from absolute zero to a temperature above the boiling point of the liquid. Which of the following processes produces the greatest increase in the entropy of the substance? A ) melting the solid B ) heating the gas C ) vaporizing the liquid D ) heating the solid E ) heating the liquid
Answer:
vaporizing the liquid
Explanation:
We generally define entropy in chemistry as the degree of disorderliness in a system. The entropy of gases is greater than that of liquids and the entropy of liquids is greater than that of solids. It then logically follows that the degree of entropy in gases is the greatest among all the states of matter while the entropy of solids is the least among all the states of matter since solid particles remain in their mean positions and can only vibrate or sometimes rotate. Liquid particles may translate while gaseous particles move at high velocity with negligible intermolecular forces of attraction between them.
A phase transition from liquid to gaseous state now represents the greatest change in the entropy of the system since gases posses the highest entropy among all the states of matter, hence the answer.
Indicators change color when an acid and a base are mixed together. The change in color most likely indicates that a chemical change has occured. a physical change has occured. a new acid has been produced. a new base has been produced.
Answer:
a chemical change
Explanation:
a physical change is mostly identified even without indicators i.e candle wax about forming a new acid or base I guess we have to include a ph scale to ascertain since the salt can be acidic but not necessarily an acid
Answer: The answer is A, a chemical change has occurred
Explanation:
I’m just a jenious
Which type of graph is best used to show how a measured quantity changes over time?
Box and whisker plot
Line graph
Circle graph
Histogram
If he wants to model a longitudinal wave that carries more energy, how should he move the end of the spring?
Answer:
they won
Explanation:
A scuba diver’s air tank contains oxygen, helium, and nitrogen at a total pressure of 205 atmospheres. The partial pressure of nitrogen is 143 atmospheres, and the partial pressure of helium is 41 atmospheres. What is the partial pressure of oxygen in the tank?
answer is 20
explanation: total Pressure = 205
partial pressure of N = 143
partial pressure of He = 41
total pressure = partial pressure of N + partial pressure of O + partial pressure of He
partial pressure of O = 205 - 185 = 20
Answer:
20
Explanation: