The question is incomplete, the complete question is;
.On heating 12.4 g of copper (II) carbonate in a crucible only 7.0g of copper (II) oxide was produced. What was the % yield of copper (II) oxide ? [Cu=64,C=12,O=16]
Answer:
87.5%
Explanation:
CuCO3 -------> CuO + CO2
Number of moles of CuCO3 = 12.4g/123.55 g/mol = 0.1 moles
Since the reaction is 1:1,
Mass of CuO produced = 0.1 moles × 80g/mol = 8 g
Hence,
% yield = actual yield/theoretical yield × 100
% yield = 7/8 × 100
% yield = 87.5%
potassium permanganate + water = ? which product will they form,and in which phase is it?
KMnO4 + H2O = MnO2 + O2 + KOH
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Please help with the Volume one
Answer:
im a just achild
Explanation:
Answer:
c
Explanation:
0.5dm³
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How much water will the measuring cup have if you poured 1/2 of it out?
Specific heat capacity is _____.
greater for metal than for wood
the amount of heat required to raise the temperature of 1g of a substance 1 oC
represented by the symbol, Q
all of these
Answer:
all of this
Explanation:
In a chemical equation, the symbol that means "dissolved in water" is _____. (s) (l) (aq) (g)
In Rutherford experiment some alpha particles fired at a gold foil bounced backward as a result of ... A.reflection from the surfaces of gold atoms B.electrostatic repulsion by gold nuclei C.electrostatic repulsion by electronsD.all of the aboveE.none of the above
Answer:
B.electrostatic repulsion by gold nuclei
Explanation:
According to Rutherford's experiment, a thin gold foil was bombarded with alpha particles. Some of the particles passed through the foil undeviated, some were scattered through large angles while some bounced backwards.
It follows that the particles that bounced backwards must have encountered a massive particle of like charge.
The atom is composed of a nucleus which contains positively charged particles. Some of the alpha particles which are positively charged particles bounced back when they encountered the positively charged particles in the nucleus.
Answer: The correct option is B (electrostatic repulsion by gold nuclei).
Explanation:
In the Rutherford's experiment, he used positively charged particles called alpha particles to bombard an atom in order to find out what is inside the atom. Together with two other scientists, Geiger and Marsden, they used a narrow beam of alpha particles emitted from a radioactive source to bombard a thin gold foil. The scattering of the particles from the gold foil was detected by a movable zinc sulphide screen which could be rotated to various positions around the foil.
Each time an alpha particle hit the screen, a visible flash of light or scintillation was produced. This was observed by a microscope attached to the screen. It was then observed that some of the particles followed a straight path through the gold foil while a few where scattered in a backward direction. This was as a result of electrostatic repulsion by gold nuclei which occurs due to the greater part of the mass of the atom was concentrated in a minute nucleus with positive charge.
The world is made up of
Answer:
Explanation:
The world is made up of living beings .
Which among the following mixtures will show tyndal effect?
i) copper sulphate solution
ii) sand in water.
iii) milk.
iv) starch solution
Answer:
milk and starch solution are the colloids, hence these will show the tyndall effect
Answer:
milk and starch solution
Explanation:
Tyndall effect is shown by colloidal solutions. It is not shown by true solutions or suspensions.
Milk and starch solution are colloidal solutions. They show tyndall effect. On the other hand, common salt and copper sulphate solution are true solutions. They do not show tyndall effect.
write any two conditions at which a body of certain mass weightless
Answer:
A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity. If the body is falling only under the influence of gravity.
Answer:
A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity.If the body is falling only under the influence of gravity.
What is the pressure in atm exerted by 1.8 g of H2 gas exert in a 4.3 L balloon at 27ºC? R = 0.821(L*atm) / (mol*K)
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The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm
What is Ideal gas law ?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
Let's convert grams to moles (via molar mass).
Molar Mass (H₂) : 2 (1.008 g/mol)
Molar Mass (H₂) : 2.016 g/mol
1.8 grams H₂ 1 mole
---------------------- x ---------------------- = 0.893 moles H₂
2.016 grams
The Ideal Gas Law equation looks like this:
PV = nRT
In this equation,
P = pressure (atm) V = volume (L) n = moles R = Ideal Gas Constant (0.0821 L*atm/mol*K)T = temperature (K)After converting Celsius to Kelvin, you can put the given values into the equation and simplify to find the pressure.
P = ? atm R = 0.0821 L*atm/mol*K
V = 4.3 L T = 27 °C + 273.15 = 300.15 K
n = 0.893 moles
PV = nRT
P (4.3 L) = (0.893 moles) (0.0821 L*atm/mol*K)( 300.15 K)
P (4.3 L) = 22.0021
P = 5.12 atm
Therefore, The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm
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Describe how to make a buffer solution using a strong base and one other reagent. 15 POINTSSSSSSSS
Answer:
Hi! hopefully this helps you
Explanation:
You can make a buffer solution for a specific pH (potential of hydrogen) by mixing together a weak acid like acetic acid HC2H3O2 with a salt that contains the conjugate base like sodium acetate NaC2H3O2. A neutralization reaction would occur as you are mixing a weak acid and a strong base.
When you add the base to an acidic solution, the solution becomes less acidic and moves toward the middle of the pH scale. Aka neutralization
Hope this helps! best of luck <3
can you answer with working out
A sample of gas has a volume of 20 cm³.The pressure is changed to 90 kPa at constant temperature,while the volume increases to 75 cm³.What was the original pressure of the gas?
Answer:
337.5kPa ~ 338kPa
Explanation:
Using the ideal gas law PV=nRT we have the following definitions from the problem:
V(initial) = 20cm³
P(initial) = ?kPa
V(final) = 75cm³
P(final) = 90kPa
Since we know that the number of moles of the sample did not change, nor did the temperature, nor does the ideal gas constant (R) we can rewrite this equation to state:
P(initial)V(initial) = nRT =P(final)V(final) ~ P(initial)V(initial) = P(final)V(final)
Rearranging this equation as we are solving for the initial pressure we find that:
P(initial) = (P(final)V(final))/V(initial)
P(initial) = ((90kPa)(75cm³))/20cm³
P(initial) = 337.5kPa ~ 338kPA
Answer the following questions based on the above graph(Electron affinity vs Atomic no.)
i)Why on moving from Li to Be, the value of electron gain enthalpy drops.
ii)Cl has a higher peak than fluorine. Explain.
iii)Why Fluorine has the highest value among its period members.
i) Be has a fully filled 2s level.
ii) This is because chlorine is larger than fluorine.
iii) Fluorine needs only one electron to attain the octet configuration.
Electron affinity is the ability of an electron to accept gaseous electrons to yield gaseous ions with a negative charge.
Electron affinity depends on the size of an atom. Larger atoms have a higher electron affinity because they are better able to accept electrons.
The drop between Li and Be is because the 2s orbital in Be is already fully filled while Li has incompletely filled 2s level. electrons do not easily go into the higher energy 2p level.
The higher peak of chlorine is because chlorine is larger than fluorine hence the electron affinity of fluorine is less than that of chlorine. The smaller the ion the lesser the electron affinity.
Fluorine has the highest electron affinity in period 2 because it needs only one electron to attain the octet structure.
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Can you help me on this. I will support your correct answer
How the amount of acid rain caused by the burning of fossil fuels can be reduced ?
Answer:
The amount of acid rain caused by the burning of fossil fuels can be reduced by creating nitrogen oxides in the process of burning coal and other fossil fuels, some power plants are changing the way they burn coal. A great way to reduce acid rain is to produce energy without using fossil fuels. Instead, people can use renewable energy sources, such as solar and wind power.
what is a cubic unit cell ?
cubic unit cell is the smallest repeated unit which have all angles equal to 90 and all have edge lengths equal
It is the type of the Unit cell which is having all angles equal to 90 and all sides equal to each other
it's is a unit cell with cubic structure
difference between Nitrogen 1 oxide and Oxygen
Answer:
one atom of oxygen is not equal to oxygen
which orbital has the lowest energy
Answer:
s orbital
Explanation:
it has the lowest energy because
Paulis law state that orbitals with lower energy must be fill first before that of higher energy
and the s orbital is filled first
1.Which of the following forms only Ionic Bond?
1)Ca 2)C 3)Si 4)P
2.How many atoms of Na are present in 92 a.m.u of it?
a)4 b)5 c)6 d)7
The Answer is A)4 atoms of NA are present in 92 a.m.u
what is the percentage composition of water in crystallization of oxalic acid
Answer:
5.17 percentage is water
Explanation:
answer from gauth math
The boiling point of water is 100ºC. The boiling point of acetone is 56ºC. Which statement about distilling a mixture of acetone and water is correct?
Acetone remains in the original container.
Water will vaporize from the mixture before acetone.
Acetone is captured and cooled.
Water is collected as it leaves the mixture.
Answer:
Acetone is captured and cooled.
Explanation:
The boiling point of acetone is lower than that of water, so it will vaporise before water. Then acetone will be captured and cooled to separate it from its mixture with water.
The statement which is correct about distilling a mixture of acetone and water is as follows:
Acetone is captured and cooled.Thus, the correct option is C.
What is Distillation?Distillation may be defined as a procedure that generally involves the conversion of a liquid into a vapor that is eventually condensed back to liquid form. With the help of this process, the separation of components or substances from a liquid mixture by using selective boiling and condensation occurs.
Acetone has the lowest boiling point as compared to water. So, it boils faster than that water and vaporizes before water. After the termination of this process, the acetone will be predominantly captured and cooled to separate it from its mixture with water.
Therefore, the correct option for this question is C.
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Cho các dung dịch: Glucozơ, glixerol, fomanđehit, etanol. Có thể dùng thuốc thử nào sau đây để phân biệt được cả 4 dung dịch trên?
A. Cu(OH)2; B. Dung dịch AgNO3 trong NH3;
C. Na kim loại; D. Nước brom.
Xem thêm tại: https://loigiaihay.com/bai-2-trang-25-sgk-hoa-hoc-12-c55a8069.html#ixzz71KH6guhm
Answer:
chắc là câu B í
Explanation:
What is the mass percent of a sodium fluoride solution prepared by dissolving 0.64 moles of sodium fluoride into 63.5 grams of water?
The mass percent of a sodium fluoride solution prepared by dissolving 0.64 moles of sodium fluoride into 63.5 grams of water is 29.7%.
What is mass percent ?Mass percent is a means to describe a component in a specific combination or to convey a concentration. The mass percentage used to describe the solution composition indicates the mass of solute contained in a given mass of solution.
To determine the mass percent of an element in a compound, we divide the mass of the element in one mole of the compound by the compound's molar mass and multiply the result by 100.
Given:
Number of moles = 0.64 moles
Moles of sodium fluoride = Given mass/molar mass
0.64 moles = Mass / 42
Mass = 26.88gram
Mass % = Mass of solute/ mass of solution × 100
= 26.88/90.48 × 100
= 29.7 %
Thus, 29.7 % is the mass percent of a sodium fluoride solution prepared by dissolving 0.64 moles of sodium fluoride into 63.5 grams of water
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What is the purpose of a catalyst in the production of hydrogen?
Select the correct answer.
- to increase the rate at which water molecules decompose
- to decrease the amount of oxygen produced
- to decrease the temperature of the reaction
- to increase the activation energy of the reaction
The purpose of a catalyst in the production of hydrogen is to increase the rate at which water molecules decompose.
What is a catalyst-A catalyst is a substance that increases the rate of a chemical reaction without itself being consumed or produced during the reaction. As a result, catalysts assist in speeding up chemical reactions while also decreasing the amount of energy needed for the reaction to occur. In hydrogen production, catalysts are used to speed up the decomposition of water into hydrogen and oxygen. The use of catalysts lowers the activation energy required for the reaction to occur, resulting in a faster reaction rate and lower operating temperatures.What is the process of hydrogen production?Hydrogen production has various methods, and one of the most commonly used methods is water electrolysis. In this method, water molecules are split into hydrogen and oxygen using an electric current passed through an electrode. Water is broken down into hydrogen and oxygen during the process, with the assistance of a catalyst. During this process, a catalyst like platinum or nickel is employed to speed up the chemical reaction of water decomposition.
When an electric current is applied to the catalyst, water molecules are broken apart, releasing hydrogen and oxygen atoms.Catalysts lower the activation energy of the reaction, allowing it to occur faster than it would otherwise. In hydrogen production, catalysts are crucial since they enable the reaction to occur at a lower temperature, reducing energy consumption and minimizing operating costs. As a result, the use of catalysts is essential to the production of hydrogen.
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help me please I will mark as brainliest for the first correct answer
Answer:
1. 3-methylpentane
2. 2-bromo-3-chloropentane
3. 2,2,4-trimethylpentane
Explanation:
1. CH3CH2CH(CH3)CH2CH3.
Methyl group is in the third carbon atom in the long chain. The organic compound has five(5) carbon atoms thus it is named as pentane.
Therefore the name of the compound is
3-methylpentane
2. CH3CH(Br)CH(Cl)CH2CH3
The compound has Chlorine and Bromine in the carbon chain. Chlorine is given as chloro-, Bromine is given as bromo, depending on the position in the carbon chain. Bromine is located in 2 carbon atom and chlorine is in third(3) carbon atom in the long chain. The long chain has five carbon atoms thus pentane.
Naming of the compound we begin with the on lowest in the alphabet. The name of the organic compound is therefore;
2-bromo-3-chloropentane
3. CH3CH(CH3)3CH(CH3)CH2CH3
In this long chained organic compound, methyl-group is found in 2,2 and 4th positions. Since this is still pentane, naming the organic compounds, we start with the one with the lowest carbon. Therefore this becomes;
2,2,4-trimethylpentane
I hope this helps you to know how to name the organic compounds.
If ya could change somethin bout ya previous science classes what would it be?
If I could change something in my previous science classes, it would have been the fact that I struggled in the question concerning exponents. It was simple one, but I don't know how I didn't understood that. For example, if there is a question with a calculation "xy²", then I would first multiply x and y, and then calculate the exponent. I did 3 of the questions wrong because of this, it was when I was in 7th grade. I wish I had not done this kind of silly mistake. I an in 10th grade and understand it well now, though.
Products formed when chlorine is produced by the electrolysis of concentrated sodium chloride solution
The products formed during electrolysis of concentrated sodium chloride solution are SODIUM HYDROXIDE and HYDROGEN GAS.
ELECTROLYSIS is the process by which electrolytes allows electric current to pass through it and is decomposed on the process.
CHLORINE is an element which can be produced industrially through the process of electrolysis of brine (concentrated sodium chloride solution). When sodium chloride is dissolved in water, it's ions separate and are capable of conducting electricity.
The products formed during this process includes:
chlorine sodium hydroxide and hydrogen gas.CHLORINE: this is released at the positive electrode during electrolysis. It is used for the following purposes:
it is used for sterilisation of water for domestic and industrial use it is used as a bleaching agent for cotton, linen and wood-pulp.SODIUM HYDROXIDE: this remains in the solution during electrolysis. It is used for the following:
processing food products, removing pollutants from water and manufacture of paper.HYDROGEN GAS:this is released at the negative electrode during electrolysis. this is used for the following:
manufacture of ammonia, hydrochloric acid and methanol it serves as constituents of many gaseous fuels such as water gas and coal gasTherefore other products during electrolysis of concentrated sodium chloride solution are SODIUM HYDROXIDE and HYDROGEN GAS.
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In the figure a cyclist moves A to B and then to C.he could also go through the shortest path AC. Depending on this fact solve the following questions: Find the length of AC .Find the displacement and total distance covered.
Answer:
hope it helps you see the attachment for further information
If 56 grams of carbon monoxide burns in oxygen to produce 88 grams of carbon dioxide, the mass of oxygen involved in the reaction is
grams.
The answer is 32 grams!
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