Answer:
The option closest to the percentage yield is option;
d. 81.1
Explanation:
The given chemical equation of the reaction is presented as follows;
CaO (s) + H₂O (l) → Ca(OH)₂
The mass of CaO in the experiment, m = 2.00 g
The volume of water with which the CaO was reacted = Excess volume of water
Number of moles = Mass/(Molar mass)
The mass of Ca(OH)₂ recovered, actual yield = 2.14 g
The molar mass of CaO = 56.0774 g/mol
The number of moles of CaO in the reaction, n₁ = 2.00 g/(56.0774 g/mol ≈ 0.036 moles
The molar mass of Ca(OH)₂ = 74.093 g/mol
The number of moles of Ca(OH)₂ in the reaction, n₂ = 2.14 g/(74.093 g/mol) ≈ 0.029 moles
From the given chemical reaction, one mole of CaO reacts with one mole of H₂O to produce one mole of Ca(OH)₂
Therefore, 0.036 moles of CaO will produce 0.036 moles of Ca(OH)₂
Mass = Number of moles × Molar mass
The mass of 0.036 moles of Ca(OH)₂ ≈ 0.036 moles × 74.093 g/mol = 2.667348 grams
∴ The theoretical yield of Ca(OH)₂ = 2.667348 grams
[tex]Percentage \ yield = \dfrac{Actual \ yield}{Theoretical \ yield} \times 100 \%[/tex]
The percentage yield = (2.14 g)/(2.667348 grams) × 100 = 80.23%
Therefore, the option which is closest is option d. 81.1.
What evidence demonstrates that chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes?
Answer:
The evidence that demonstrated that the Chlorine in the stratosphere is believed to come primarily from CFCs ( Chlorofluorocarbons) rather than from natural sources such as volcanoes was due to the study conducted in which the amount of chlorine in the stratosphere over the past 20 years was measured and it was discovered that there was an increase over the years. This also corresponded with a rise in CFCs over the same period which shows that the chlorine in the stratosphere was from man made chemicals such as chlorofluorocarbons.
Chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes is evident as follows;
Discussion;
Most of the chlorine in the stratosphere is there as a result of human activities, as the figure below illustrates.
Many compounds containing chlorine are released at the ground.
Volcanoes can emit large quantities of hydrogen chloride, but this gas is rapidly converted to hydrochloric acid, which dissolves in rain water, ice, and snow and does not reach the stratosphere.
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Can someone plz help me :<
Answer: cats r alliens because they r kind of like ufos they would usually wonder around rather u know it or not when they spy on us it could b with us sleep cooking anything so they r like aliens
Explanation:
PLEASE HELP!! What direction do you predict the addition of a base to the solution containing bromophenol blue will drive the equilibrium? Explain your prediction in terms of Le Châtelier's principle.
Answer:
Below is the clarification of that same particular question.
Explanation:
Le Chatlier's theory states that whenever an equilibrium mechanism is disrupted by environmental influences, the program responds by changing the supplies information of its constituents in a somewhat way that the disturbance is invalidated and reaches a stable equilibrium during that disrupted stage, with concentrations of stability differently than ever before.Bromothymol blue seems to be a phenolic subs lone which always allows it to act throughout aqueous solutions as an acidic solution. Being such an acid (weak), it should not add to rapid, as well as introduces a balance with its accompanying but mostly disconnected form.For that kind of weak diprotic predictor, the standard economic statement can indeed be published as:
⇒ [tex]H_2In_(aq)\rightleftharpoons In^{2-} +2H^+[/tex]
It could be conclusively proven from either the theory of Le Charlier whereby, that whenever a strong acid becomes applied, the full disorientation of one or the other, through equilibrium formation, induces an increase throughout the medium's proton concentrations.Likewise, it absorbs the protons throughout the media to split water that whenever a solution is added. So, particle concentration throughout the medium is decreasing. To accommodate for this transition, the equilibrium reacts by moving to the correct i.e. causing further dissociation of the optimistic predictor into their dianion through protons, thereby attempting to nullify that perturbation.In a reversible reaction, the endothermic reaction absorbs ____________ the exothermic reaction releases.
A. None of these, endothermic reactions release energy
B. more energy than
C. the same amount of energy as
D. less energy than
Answer:
C. the same amount of energy as
Explanation:
Firstly, a chemical reaction can either absorb energy from its surroundings to occur or release energy into its surroundings as a product. The former and latter descriptions are called ENDOTHERMIC and EXOTHERMIC reactions respectively. An exothermic reaction is that which transfers energy, in form of heat, to its surroundings while an Endothermic reaction is that which absorbs energy (heat) from its surroundings.
However, a reversible reaction is that reaction in which the formation of products from reactants and reformation of the reactants from products occur simultaneously. Hence, the products of a reversible reaction can become the reactants and move in the opposite direction. For example:
Reversible reaction: A + B ⇆ C + D means;
A + B → C + D and;
C + D → A + B
In a case whereby the opposite reactions consist of an endothermic and exothermic reactions, the endothermic reaction absorbs the same amount of energy as the exothermic reaction releases.
According to the law of conservation of energy, no energy is lost during a reversible reaction. Hence, in order to achieve an equilibrium, the amount of energy absorbed by the endothermic reaction is the same as the amount of energy released in the opposite exothermic reaction.
The table describes how some substances were formed.
Substance
P.
Q
Description
Formed by boiling pure water
Formed by combining three hydrogen atoms to every nitrogen atom
Formed by adding 5 g of sugar to 1 L of water
Formed by compressing carbon under high pressure
R
S
Based on the given descriptions, which substance is most likely a mixture?
P
Q
R
S
Explanation:
Which is a pure substance?
1. soda
2. gasoline
3. salt water
4. carbon dioxide
carbon dioxide
Bromine, a liquid at room temperature, has a boiling point of 58°C and a melting point of -7.2°C. Bromine can be classified as a
1. compound.
2. impure substance.
3. mixture.
4. pure substance.
pure substance.
Answer:
the answer is
Explanation:
Sugar and water make a homogeneous mixture (the same proportions of its components throughout any given sample).
Which of the following pairs of compounds have the same empirical formula?
a. acetylene, C2H2, and benzene, C6H6
b. ethane, C2H6, and butane, C4H10
c. nitrogen dioxide, NO2, and dinitrogen tetroxide, N2O4
d. diphenyl ether, C12H10O, and phenol, C6H5OH
Answer:
option a and c both are correct
Explanation:
please mark me as brainliest
The pairs of compounds have the same empirical formula are:
a. acetylene, C₂H₂, and benzene, C₆H₆ and
c .nitrogen dioxide, NO₂, and di nitrogen tetroxide, N₂O₄
What is empirical formula?The empirical formula of a compound is defined as the formula that shows the ratio of elements present in the compound, but not the actual numbers of atoms found in the molecule.
In some cases, the empirical formula is the same as the molecular formula, which gives the actual number of atoms in a compound (e.g., H₂O).Otherwise, the molecular formula is a multiple of the empirical formula (e.g., CH₂O is the empirical formula for glucose, C₆H₁₂O₆).
Examples of empirical formulas:
Glucose has a molecular formula of C₆H₁₂O₆. It contains 2 moles of hydrogen for every mole of carbon and oxygen. The empirical formula for glucose is CH₂O.
The molecular formula of ribose is C₅H₁₀O₅, which can be reduced to the empirical formula CH₂O.
The pair with empirical formula is acetylene, C₂H₂, and benzene, C₆H₆ and
nitrogen dioxide, NO₂, and di nitrogen tetroxide, N₂O₄
Thus, option (A) and (C) are correct.
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3. How did ethanol use affect the shortage of corn available to consumers during and
after the drought of 2012? Do you think that commodities in one sector should be used
in another economic sector? How might the concept of needs and wants affect your
analysis of this issue?
Due to drought, the production of corn decreases and shortage of it occurs.
Effects of droughtYes, commodities in one sector should be used in another sector because scientist invented methods in which one commodity is used in several sectors for the production of new products.
Corn was used for the production of ethanol which causes the shortage of corn that was available to consumers during and after the drought condition of 2012 so we can conclude that due to drought, the production of corn decreases and shortage of it occurs.
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A student is worried about determining if a chemical is radioactive. Which
section of the SDS would the student refer to?
Product Information
Fire Fighting Methods
Physical and Chemical Properties
Hazards Identification
Answer:
Hazards Identification
Explanation:
A safety data sheet, SDS, is an informational document provided by the manufacturer or importer of a hazardous chemical detailing the chemical, physical, health, and environmental health hazards associated with the chemical as well as safety precautions in handling the chemical.
Some of the sections in the SDS include:
Product Information: It identifies the chemical as well as its recommended uses. The contact information of the manufacturer is also provided.
Fire fighting methods: It gives measures and guidelines necessary for fighting a fire caused by the chemical.
Physical and chemical properties: states the physical and chemical properties of the chemical substance such as: appearance, odor, pH, melting/freezing point, boiling point and boiling range, flammability, etc.
Hazards identification: states the hazards of the chemical and the necessary warnings regarding the hazards. Some of the information provided include: hazard classification of the chemical (for example flammable liquid, oxidizing gases,explosives, etc), signal word, hazard statement (for example radioactive), pictograms, precautionary statements, etc.
From the above information provided, the student should refer to the hazards identification section.
Answer in the correct significant figures: 35.6 + 56.27 *
Answer:
101.87
Explanation:
that's the answer
why there are two chloride ions for every calcium ion
Answer:
The valency of calcium is +2
Explanation:
Calcium is in group two. The members of group two are divalent metals that loose two electrons to form M^2+.
Since they form M^2+, they form ionic bonds with two uninegative ions. Chlorine is in group 17. This implies that its valency is -1 and it accepts one electron when it participates in an ionic bond.
Hence it will take two chlorine atoms to receive two electrons from one calcium atom in an ionic bond making the ratio of calcium to chlorine in the compound 2:1.
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
In an electrochemical cell, equilibrium is the point at which:
A. None of these
B. both electrodes have an equal number of electrons.
C. ion concentrations are no longer changing and the voltage is 0.
D. Equilibrium cannot be reached in a voltaic cell because electrons only flow in one direction.
Answer:
C. ion concentrations are no longer changing and the voltage is 0.
Explanation:
Electrochemical cells are a device that generates current from redox reactions. In the cell, the equilibrium is reached when the voltage drops to 0. Thus, option C is correct.
What is an electrochemical cell?An electrochemical cell is a voltaic device that uses chemical energy to generate electrical energy and vice versa. It is of two types electrolytic and galvanic cells depending on the energy it produces.
The electrochemical cell comprises two electrodes namely an anode and cathode, a salt bridge or the porous barrier, and an external connection.
The connection shows the voltage that indicates the equilibrium. When the current flow stops and the voltage reaches zero, the electrochemical cell is said to be in equilibrium.
Therefore, no change in the ionic concentrations and zero voltage indicates equilibrium.
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which property is a physical property
Answer:
a
Explanation:
because it is matter . It has change in molèculaŕ level
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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Which of the following is an aldehyde?
Answer:
D
Explanation:
I wish it will help you thank you
An aldehyde is a functional group that has the general formula CₓH₂ₓ₊₁CHO. The compound in option C is an aldehyde. Thus, option C is correct.
What is an aldehyde?An aldehyde is a type of functional group that has a carbon atom that shares a double bond with an oxygen atom and another single bond with the R group and H group (R−CH=O).
The aldehyde functional group gives a specific chemical property to the species. The first compound is CH₃CH₂CH₂COOH is a carboxylic acid functional group. The second compound is CH₃CH₂CH₂COOCH₃ is an ester.
The third compound is CH₃CH₂CH₂CHO an aldehyde group as (R−CH=O) functional group is present. The fourth compound is CH₃CH₂CH₂COCH₃, ketone.
Therefore, option C is an aldehyde.
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What is the product of the reaction of pentanoic acid with ethanol in the presence of a strong acid?
Answer:
ethylpentanoate
Explanation:
Alkanoic acids react with alkanols in the presence of mineral acids to yield an ester and water. This is the organic analogue of the inorganic neutralization reaction. The reaction his commonly called esterification. It is an acid catalysed reaction.
The reaction of pentanoic acid and ethanol in the presence of a string acid is shown below;
CH3CH2CH2CH2COOH(aq) + CH3CH2OH(aq) ----> CH3CH2CH2CH2COOCH2CH3(aq) + H2O(l)
The name of the compound formed is ethylpentanoate.
You are given two aqueous solutions with different ionic solutes (Solution A and Solution B). What if you are told that Solution A has a greater concentration than Solution B by mass percent, but Solution B has a greater concentration than Solution A in terms of molality? Is this possible? If not, explain why not. If it is possible, provide example solutes for A and B and justify your answer with calculations.
Answer:
Yes, it is possible. Let us consider an example of two solutions, that is, solution A having 20 percent mass RbCl (rubidium chloride) and solution B is having 15 percent by mass NaCl or sodium chloride.
It is found that solution A is having more concentration in comparison to solution B in terms of mass percent. The formula for mass percent is,
% by mass = mass of solute/mass of solution * 100
Now the formula for molality is,
Molality = weight of solute/molecular weight of solute * 1000/ weight of solvent in grams
Now molality of solution A is,
m = 20/121 * 1000/80 (molecular weight of RbCl is 121 grams per mole)
m = 2.07
Now the molality of solution B is,
m = 15/58.5 * 1000/85
m = 3.02
Therefore, in terms of molality, the solution B is having greater concentration (3.02) in comparison to solution A (2.07).
7.95x10 converted to the number is
7.95 × 10
= 79.5
This is the answer
in h-atom if x is radius of first bohrs orbit de broglie wavelength of an atom in 3rd orbit is a.3πx b.6πx c.9x/2 d.x/2
please I need complete explanation fast
Answer:
can you type question properly.
calculate the volume of hydrogen produced at s.t.p when 25g and zinc are added to excess dilute hydrochloric acid at 31 degrees and 778 mm Hg pressure ( H= 1 , Zn = 65 , cl = 35.5 , volume of gas at stop = 22.4 dm cube
Answer:
The volume of hydrogen gas produced at s.t.p. is 9.419 dm³
Explanation:
The balanced chemical equation for the reaction is given as follows;
Zn + 2HCl → ZnCl₂ + H₂
Therefore, we have;
One mole of Zn reacts with 2 moles of HCl to produce one mole of ZnCl₂ and one mole of H₂
Number of moles of Zn present = 25/65 = 5/13 = 0.385 moles
Therefore, number of moles of H₂ produced = 0.385 moles
The volume of hydrogen gas produced is given by the relation
PV = nRT, we have;
R = 8.3145 J/(mol·K)
V = nRT/P = 0.385 ×8.3145 ×298.15/(101325)= 0.009419 m³ = 9.419 dm³
The volume of hydrogen gas produced at s.t.p. = 9.419 dm³.
balance this equation
Si Cl4 + H2O → Si (OH4) + HCl
Please give a detailed explanation
Answer:
4HCl + SiO2 → 4H2O + SiCl4
axit clohidric Silic dioxit nước Silic tetraclorua
Axit
Explanation:
Answer:
SiCl4 + 4H2O--->Si(OH4)+4HCl
Explanation:
if you put a 4 in front of H2O it means you will have 8 hydrogens(you multiply 4 by 2) then the oxygens will be 4..on the other side that hydrogen in the brackets holds it's on 4 so that 4 isn't for both the hydrogen and the oxygen...and if you put a 4 in front of the HCl that simply means it's for both the hydrogen and oxygen.
I hope this helps
What type of reaction is shown below:
Ethanoic acid + propanol -> propyl ethanoate + water
A. Polymerization
B. Addition (water)
C. Elimination
D. Esterification
Answer:
c
Explanation:
because mix with propanol
4. (01.05 MC)
Rubbing alcohol evaporates from your arm quickly, leaving a cooling effect on your skin. How do the molecules of gas compare to the molecules as a liquid? (4 points)
The gas particles move faster, have the same molecular composition, and have weaker attractions between them than the liquid particles
The gas particles move faster than the liquid particles, and the bonds of the molecules are broken during evaporation to allow gas atoms to spread apart.
The gas particles move slower but have the same molecular structure and the same attraction between them as the liquid particles.
The gas and liquid particles move at the same speed, but the bonds of the molecules are broken during evaporation to allow the gas atoms to spread apart
Answer:
The correct option is;
The gas particles move faster, have the same molecular composition, and have weaker attractions between them than the liquid particles
Explanation:
The properties of the gas molecules in comparison to liquids are
1) The gas molecules are widely spread out
2) After evaporation and while in conditions favorable to the gaseous state, the kinetic energy of a gas is larger than the inter molecular attractive forces
3) A gas fills the container in which it is placed
For liquids
1) There are strong intermolecular forces holding the molecules together in a liquid
2) Liquid attractive forces in a liquid are strong enough to hold neighboring molecules
3) The volume of a liquid is definite.
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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. Fire can be extinguished by: - a. Lowering temperature below ignition temperature b. Cutting the supply of oxygen c. Removing non-combustible substances from surroundings d. Both a & b
Answer:
B. Cutting the supplies of oxygen
Use Charles's Law to solve the following problem. A sample of air has a volume of 550.0 mL at 106 °C. At what temperature will its volume be 700.0 mL at constant pressure?
a
482 K
b
63 °C
c
505 K
d
119 °C
Answer:
im not sure but i think its c
505 K
describe an activity to separate the mixture of sand and water
Answer:
Sedimentation and decantation
Explanation:
Sedimentation and decantation: Mixture is kept undisturbed for some time. After some time, sand being heavier and insoluble in water, settles down at the bottom of container. Now, water is poured into another container to separate it from sand.
Answer:
evaporation or destillation
Explanation:
When sand is added to water it either hangs in the water or forms a layer at the bottom of the container. Sand therefore does not dissolve in water and is insoluble. It is easy to separate sand and water by filtering the mixture. Salt can be separated from a solution through evaporation.
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.
Please help...
Draw a diagram showing the bonding in:
a) Tetrachloromethane [CCI4]
Answer:
here u go! ................
Answer:
Hope this is ok :))
Explanation:
differences between properties of convalent and ionic bond.
Ionic bonds will be a metal + a nonmetal, and electrons
are transferred from the metal to the nonmetal.
A covalent bond will be a nonmetal only. Nonmetals will not give up their electrons so electrons are shared.
I have also written this on the whiteboard in the image provided.