Answer:
The abundance of the 13C isotope is 1.115%
Explanation:
The given information are;
Common isotope of carbon are 12C and 13C
The formula for calculating the relative atomic mass is the observed mass multiplied by the percentage abundance at that mass given as follows;
M₁ X₁ + M₂X₂ = Relative atomic mass
Where:
X₁ + X₂ = 1 as these are percentage represented as fractions
Let M₁ = 12 for 12C and M₂ = 13 for 13C
X₁ = Relative abundance fraction of 12C
X₂ = Relative abundance fraction of 13C
We have;
12X₁ + 13X₂ = 12.01115.......................(1)
X₁ + X₂ = 1............................................(2)
Which gives;
X₁ = 1 - X₂
Substituting the value for X₁ in equation (1) gives;
12(1 - X₂) + 13X₂ = 12.01115
13X₂ - 12X₂ + 12 = 12.01115
X₂ = 12.01115 - 12 = 0.01115
Therefore, the relative abundance fraction of 13C 0.01115 which in percentage is 100 × 0.01115 = 1.115%.
2. If the reaction of 5.75 moles of sodium with excess hydrofluoric acid is able to produce 2.49 mol H2, what is the percent yield of hydrogen gas?
Unbalanced equation:
Na + HF –> NaF + H2
94.2%
86.5%
43.3%
23.1%
Answer:
86.5%
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
2Na + 2HF –> 2NaF + H2
Next, we shall determine the theoretical yield of the hydrogen gas, H2. This is illustrated:
From the balanced equation above,
2 moles of Na reacted to produce 1 mole of H2.
Therefore, 5.75 moles of Na will react to produce = (5.75 x 1)/2 = 2.88 moles of H2.
Therefore, the theoretical yield of Hydrogen gas, H2 is 2.88 moles.
Finally, we shall determine the percentage yield of Hydrogen gas, H2. This can be obtained as follow:
Actual yield of H2 = 2.49 moes
Theoretical yield of H2 = 2.88 moles
Percentage yield of H2 =.?
Percentage yield = Actual yield /Theoretical yield x 100
Percentage yield = 2.49/2.88 x 100
Percentage yield = 86.5%
Therefore, the percentage yield of Hydrogen gas, H2 is 86.5%.
How many grams of NO are produced from 15.8 g of H2O
Answer:
26.33 g of NO.
Explanation:
We'll begin by writing the balanced equation to produce NO from H2O. This is given below:
5N2 + 6H2O —> 4NH3 + 6NO
Next, we shall determine the mass of H2O that reacted and the mass of NO produced from the balanced equation. This is illustrated below:
Molar mass of H2O = (2x1) + 16 = 18 g/mol
Mass of H2O from the balanced equation = 6 x 18 = 108 g
Molar mass of NO = 14 + 16 = 30 g/mol
Mass of NO from the balanced equation = 6 x 30 = 180 g
From the balanced equation above,
108 g of H2O reacted to produce 180 g of NO.
Finally, we shall determine the mass of NO produced by the reaction of 15.8 g of H2O.
This is illustrated below:
From the balanced equation above,
108 g of H2O reacted to produce 180 g of NO.
Therefore, 15.8 g of H2O will react to produce = (15.8 x 180)/108 = 26.33 g of NO.
Therefore, 26.33 g of NO were obtained from the reaction.
What is the shape of a molecule of CH4?
O A. Trigonal-bipyramidal
O B. Bent
O C. Trigonal-pyramidal
O D. Tetrahedral
Answer:
D. Tetrahedral
Explanation:
the reason is because four electron pairs are distributed.
How many Liters of 18 M H2SO4 are needed to make 0.5 L of 1.5 M H2SO4
Answer:
0.04 L
Explanation:
The following data were obtained from the question:
Concentration of stock solution (C1) = 18M
Volume of stock solution needed (V1) =?
Concentration of diluted solution (C2) = 1.5M
Volume of diluted solution (V2) = 0.5L
The volume of the stock solution needed can be obtain by using the dilution formula.
This is illustrated below:
C1V1 = C2V2
18 x V1 = 1.5 x 0.5
Divide both side by 18
V1 = (1.5 x 0.5)/18
V1 = 0.04L
Therefore, the volume of the stock solution needed is 0.04L.
We learned about three career opportunities in the field of pulp and paper in class. Pick one career and find out the education, training, and experience required for this profession. Write about what you found and explain why this profession might interest you
Answer:
Pulp and Paper technology is a specialist field of chemical engineering which involves the study of the processes required for the conversion of raw materials such as wood, into pulp and paper products.
Paper and pulp manufacturing is a growing and dynamic industry so it requires a wide variety of personnel - from unskilled and semi-skilled workers to tradesmen, technicians and engineers - to control all the processes and develop new ones.
I choose to be a chemist in the field of paper and pulp. Requirements and compulsory Subjects: Physical Sciences, Mathematics, Engiineering and Technology.
Chemists are responsible for quality control and they study the influence of various chemicals on pulp and paper. Chemical and mechanical engineers develop new production methods.
I'll like to be a chemist in the field of paper and pulp because they perform the major role in the chemical properties of the paper and pulp.
Explanation:
Hope it helps.
Answer:
PLATO ANSWER
Explanation:
Which statement correctly describes Earth’s magnetic field?
A) A compass can lead a hiker to the geographic North Pole.
B) The magnetic pole near the South Pole is a north pole.
C) Compasses point toward a magnetic pole that is a north pole.
D) Field lines circle Earth from east to west.
Answer:
B) The magnetic pole near the South Pole is a north pole.
Explanation:
The north pole on the compass is the geographical South Pole.
Hope it helps.
Answer:
The answer is B.
Explanation:
Consider preparing ammonia gas by the following reaction:
N2(g) + 3H2(g) ===> 2NH3(g)
If you have 28.02 g of N2 and excess H2, how many grams of NH3(g) can be produced.
6.06g
14.01g
34.08 g
68.16 g
28.02g
Answer:
34.08g
Explanation:
(Take the atomic mass of N=14.0, H=1.0)
no. of moles = mass / molar mass
no. of moles of N2 used = 28.02 / (14x2)
= 1 mol
Since H2 is in excess and N2 is the limiting reagent, the no. of moles of NH3 produced depends on the no. of moles of N2 used.
From the equation, the mole ratio of N2:NH3 = 1: 2,
which means one mole of N2 produces 2 moles of NH3.
From the ratio, we can deduce the no. of moles of NH3 produced = 1 x 2 =2moles.
Mass = no. of moles x molar mass
Mass of NH3 produced = 2 x (14.0+1.0x3)
= 34g
≈34.08g (this happens because the atomic mass I took is only corrected to 1 decimal place, but in the end, this is only a very small error in the decimals. Make sure you take a look if the question provides the atomic mass:) )
Bee stings release methanoic acid which attacks the nerves in the skin. They can be
neutralized by applying a cream that contains
a) ammonia
b) vitamin C
c) sulphur dioxide
d) acetic acid (vinegar)
Answer:and so an acid should be applied to neutralize them and remove the pain.
Explanation:Bee and Wasp stings can be both painful and itchy, and are very common ... Many common household substances can be used for this, and vinegar and ... If you are near other Bees and Wasps,
Ammonia can be used to neutralise. Hence, option A is correct.
What is methanoic acid?It is the simplest carboxylic acid which consists of a single carboxylic acid group (COOH) which is attached to a hydrogen atom.
Ammonia is a great way to help neutralise the venom of a bee sting. All you need to do is create a thick paste out of baking soda and water and apply it to the sting.
Hence, option A is correct.
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Determine the [H+] or [OH−] for each of a solutions at 25°C.
Solution B: [H3O+] = 9.99 x 10^-9 M
Solution B: [OH-] = ?
Solution C: [H3O+] = 0.000777 M
Solution C: [OH-] = ?
Answer:
Solution B: [OH-] = 1×10^–6 M
Solution C: [OH-] = 1×10^–6 M
Explanation:
Solution B:
Hydronium ion concentration, [H3O+] = 9.99×10^–9 M
Hydroxide ion concentration, [OH-] = ?
The Hydroxide ion concentration, [OH-] can be obtained as follow:
[H3O+] × [OH-] = 1×10^–14
9.99×10^–9 × [OH-] = 1×10^–14
Divide both side by 9.99×10^–9
[OH-] = 1×10^–14 / 9.99×10^–9
[OH-] = 1×10^–6 M
Therefore, the Hydroxide ion concentration, [OH-] is 1×10^–6 M
Solution C:
Hydronium ion concentration, [H3O+] = 0.000777 M
Hydroxide ion concentration, [OH-] = ?
The Hydroxide ion concentration, [OH-] can be obtained as follow:
[H3O+] × [OH-] = 1×10^–14
0.000777 × [OH-] = 1×10^–14
Divide both side by 0.000777
[OH-] = 1×10^–14 / 0.000777
[OH-] = 1.29×10^–11 M
Therefore, the Hydroxide ion concentration, [OH-] is 1.29×10^–11 M
1. A 10.0 g sample of propane, C3H8, was combusted in a constant-volume bomb
calorimeter. The total heat capacity of the bomb calorimeter and water was 8.0
kJ/°C. The molar heat of combustion of propane is -2 222 KJ/mol. If the starting
temperature of the water was 20 °C, what will be the final temperature of the
bomb calorimeter?
Answer:
The final temperature of the bomb calorimeter is 82.98°C
Explanation:
The given information are;
The mass of the propane sample = 10.0 g
The heat capacity of the bomb calorimeter = 8.0 kJ/°C
The molar heat of combustion of propane is -2,222 kJ/mol.
The starting (initial) temperature of the water, T₁ = 20°C
The final temperature of the bomb calorimeter = T₂
The molar mas of propane = 44.1 g/mol
The number of moles, n, of propane present in 10.0 g of propane is found as follows;
[tex]Number \ of \ moles \ of \ propane, \ n = \dfrac{Mass \ of \ propane}{Molar mass \ of \ propane} = \dfrac{10}{44.1} = 0.227 \ moles[/tex]Which gives;
The heat, Δh, released from the combustion of 10.0 g of propane = 0.227 × -2222 kJ/mol
Δh = -503.85 kJ/mol
Heat gained by the calorimeter = Heat released from the combustion of 10.0 g of propane = 503.85 kJ/mol
Change in heat, Δh[tex]_c[/tex] in the calorimeter = Heat capacity × Temperature change
Δh[tex]_c[/tex] = m × C
503.85 kJ/mol = 8.0 kJ/°C × (T₂ - 20°C)
T₂ = -503.85 kJ/mol/(8.0 kJ/°C) + 20°C = 82.98°C
The final temperature of the bomb calorimeter = 82.98°C
One mole of any gas at room
temperature and pressure will
occupy liter(s).
A. 10
B. 1
C. 22.4
D. 24
Reset Selection
One mole of any gas at room temperature and pressure will occupy 22.4 liter(s) (option C).
What is an ideal gas?Ideal gas is an hypothetical gas, whose molecules exhibit no interaction, and undergo elastic collision with each other and with the walls of the container.
One mole of an ideal gas contains a volume of 22.414 L at standard temperature and pressure (STP).
According to Avogadro's law, the volume occupied by one mole of a gas must be the same for all gases if the temperature and pressure are the same.
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SERE
What type of energy is the sum of an object's potential and kinetic energy?
mechanical energy
electromagnetic energy
chemical energy
thermal enemy
Answer:
Mechanical energy
Answer:
Mechanical Energy
Explanation:
The mechanical energy is the sum of the objects potential energy (energy the object possess due to its position) and its kinetic energy (energy the object possess due to its motion). Adding this two energies together, gives the total mechanical energy.
Scientists hypothesize that a certain species of animal existed in the past.
But, fossils of the species have never been found. Which two statements
could explain why?
A. There were very few members of the species.
B. Their bodies decomposed quickly.
O C. Their bodies contained radioactive atoms.
D. Minerals seeped into their bones.
SUBMIT
Answer: Fossils of the species have never been found because:-
a. There were few members of the species.
d. Their bodies decompose quickly.
For an organism to become fossil it is important that it do not decompose before it get buried by sediments.
What are fossils?
A fossil is any preserved remains, impression, or trace of any once-living thing from a past geological age.
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Answer: The answer is B and A.
Explanation:
I took the test!
What is an example of an internal stimulus to which plants can respond? 1. temperature 2. hormones 3. soil conditions 4. light
Answer:
Hormones
Explanation:
Temperature, soil conditions, and light are all external stimuli that the plants can respond to; therefore, hormones would be the only internal stimulus.
In the equation 2KCIO3 → 2KCI + 302, how many moles of oxygen are produced when 12.61 mol of
KCIO3 decompose completely?
Select one:
O a. 19
Ob. 8.4
O c. 6.3
O d. 13
PLEASE I AM BEGGING PLEASE HELP ME
Answer:
A 19
Explanation:
2 mole of KClO3 produces 3 mole of O3
2 : 3
1 : 3/2
12.61 : 3/2 × 12.61
12.61 : 18.9
12.61 mole of KClO3 produces 18.9mole of O2.
In what way does the shape of a molecule affect how the molecule is involved with living systems?
A. It determines the weight of a molecule
B. it determines what elements are in a molecule
C. it determines oxidation states present in a molecule
D. it determines how the molecule functions
There are two characteristics of molecules, one is geometry and other is shape. Shape is excluding lone pair surrounding the central element and geometry is including the lone pair. Therefore, the correct option is option D.
What is VSEPR theory?VSEPR stands for valence shell electron pair repulsions. VSEPR theory is used to predict the shape and geometry of molecules on the basis of valence electrons pairs that are present around the central element of the molecule.
According to VSEPR theory, Lone pair lone pair repulsion is greater than bond pair bond pair repulsion. There are so many limitations of VSEPR theory. There is a repulsion between bond pair electrons and lone pairs present on the central element. The shape of a molecule affect how the molecule is involved with living systems as it determines how the molecule functions.
Therefore, the correct option is option D.
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The functional group for an ester is: RCHO RCOOH RCOOR ROH
Answer:
RCOOR
Explanation:
Odyssey ware
RCOOR is the functional group for an ester. An ester is an organic molecule created when an acid and an alcohol interact. The general structure of the compound is RCOOR, where R is an aryl or alkyl group.
What is the way for the structure ?This functional group is made up of an alkyl or aryl group (R) and a carbonyl group (C=O) linked to an oxygen atom. Two additional carbon atoms, one of which is a member of the carbonyl group and the other of which is a member of the alkyl or aryl group, are joined to the oxygen atom.
The connection between the oxygen atom and the hydrogen atom of the acid is broken during the interaction of an acid with an alcohol to create an ester.of a fresh connection between the oxygen atom and the alcohol's alkyl or aryl group. As a result, the RCOOR functional group is created.
Esters are significant organic substances with many different uses. They serve as solvents and are employed in the synthesis of flavours, perfumes, polymers, medicines, and other products. They are also employed in the creation of fragrances and cosmetics, as well as as lubricants. Other organic compounds can be made using esters as intermediates.
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Which of the following is a polar molecule?
O A. A carbon monoxide molecule (CO)
OB. A linear carbon dioxide molecule (CO2)
OC. A calcium oxide molecule (Cao)
O D. An oxygen molecule (0)
Answer:
D. An oxygen molecule (0)
Explanation:
Hope it helps.
At a certain temperature, Ke = 3 for the reaction NO3(g) NO(g) + O2(g) Find the direction of thereaction if at some point in time in a 1.0 vessel the following respective concentrations were measured; [NO] = 2.0 mol/L, [O2] = 1.0 mol/L and NO3(g) = 0.75 mol/L.
What is measured by the reaction rate? the probability that a reaction will occur the speed at which products form the time required for a reaction to go to completion
Answer: the speed at which products form
Explanation:
Rate of a reaction is defined as the speed at which a chemical reaction proceeds. It is often expressed in terms of the concentration of a reactant that is consumed in a unit time or the concentration of a product that is formed in a unit of time.
For a general reaction :[tex]A\rightarrow B[/tex]
[tex]Rate=-\frac{d[A]}{dt}[/tex]
or [tex]Rate=+\frac{d[B]}{dt}[/tex]
where d[A] = change in concentration of reactant A
d[B] = change in concentration of product B
dt = time interval
Scientists disagree about the possible effects of global warming. Please select the best answer from the choices provided T F this would be appreciated
Scientific evidence for warming of the climate system is unequivocal.
The current warming trend is of particular significance because most of it is extremely likely (greater than 95 percent probability) to be the result of human activity since the mid-20th century and proceeding at a rate that is unprecedented over decades to millennia.
Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. This body of data, collected over many years, reveals the signals of a changing climate.
The heat-trapping nature of carbon dioxide and other gases was demonstrated in the mid-19th century.Their ability to affect the transfer of infrared energy through the atmosphere is the scientific basis of many instruments flown by NASA. There is no question that increased levels of greenhouse gases must cause the Earth to warm in response.
Answer:
this is false
Explanation:
1. Give IUPAC for the following compound
Answer:
Ethane
Explanation:
In the past mining companies were not made responsible for the clean-up of any of
the mine sites. As a result, abandoned mines had a severe impact on the
environment in Ontario. Which of these is not a result of these mining practices?
a)
Chemical reactions producing sulphuric acid decrease soil and water ph in the
area.
b)
Acid leaching dissolves metals found in the soil thus allowing them to enter
the water system.
c)
Heavy metals which are left tailing ponds can dissolve and enter the water
system.
d)
Old and inefficient mining smokestacks contaminate the soils around
abandoned mine sites.
The overall process of photosynthesis has the balanced chemical equation 6CO, +6H,0 CH.0, 60, What does this tell you about the relative amounts of carbon
dioxide and water consumed in this process?
A. For every six moles of carbon dioxide consumed, one mole of water is consumed
B. For every mole of carbon dioxide consumed, one mole of water is consumed
C. For every gram of carbon dioxide consumed, one gram of water is consumed
D. For every six grams of carbon dioxide consumed, one gram of water is consumed.
Answer:
(C)
Explanation:
Because of the physics of it.
According to the overall equation of photosynthesis as follows: 6CO2 + 6H2O = C6H12O6 + 6O2, for every mole of carbon dioxide consumed, one mole of water is consumed.
What is photosynthesis?Photosynthesis is the process by which plants and other photoautotrophs convert light energy into chemical energy.
Photosynthesis makes use of carbon dioxide and water to produce glucose and oxygen as follows:
6CO2 + 6H2O = C6H12O6 + 6O2
This chemical equation suggests that for every mole of carbon dioxide consumed, one mole of water is consumed.
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Plants can only
cause mechanical weathering.
Please select the best answer from the choices provided
OT
OF
Answer:
Ice wedging, pressure release, plant root growth, and abrasion can all cause mechanical weathering. in the cracks and pores of rocks, the force of its expansion is strong enough to split the rocks apart. This process, which is called ice wedging, can break up huge boulders.
Answer:
f
Explanation:
The pH of a substance can only be determined when it is
a) dried in a powder
b) frozen
c) dissolved in water
d) heated
The pH of a substance can only be determined when it is frozen. Hence, option B is correct.
What is pH?pH stands for Hydrogen potentials.
The use of the pH scale is one practical way of quantitatively determining how acidic something is.
If the pH of a solution is less than 7, it is acidic. If the pH is 7, the solution is neutral and if the pH is greater than 7,the solution is basic.
The pH of a substance can only be determined when it is frozen. Hence, option B is correct.
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Q10. Calcium fluoride can be made from the reaction of calcium metal with fluorine gas. The image shows this reaction. Explain how the product is formed in terms of electron movement and what the final electron configurations are
Answer:
The answer to your question is given below
Explanation:
In this reaction, the calcium metal, Ca loses two electrons to form calcium ion, Ca^2+ and two fluorine atoms, F receives the two electrons to form two fluoride ion, F^-.
This is illustrated by the following equation:
Ca —> Ca^2+ + 2e
2F + 2e –> 2F^-
Ca + 2F + 2e —> Ca^2+ + 2F^- + 2e
Cancel out 2e
Ca + 2F —> Ca^2+ 2F^-
Thus, the electronic configuration can be written as follow:
Before combination:
Calcium, Ca (20) => 2, 8, 8, 2
Two fluorine atom, F (9) => 2, 7 and 2, 7
After combination:
Calcium ion, Ca^2+ => 2, 8, 8
Two fluoride ion, F^- => 2,8 and 2,8
Calculate the number of moles in 25.0 g of each of the
following:
a. He
b. 02
c. Al(OH)3
d. Ga S3
e. C4H10, butane
Answer:
A. 6.25moles
B. 0.78moles
C. 0.32moles
D. 0.15moles
E. 0.43moles
Explanation:
use
n = mass/molar massA. He
25/4 = 6.25molesB. O2
25/32 = 0.78molesC. Al(OH)3
27+ 3(17) = 7825/78 = 0.32 molesD. GaS3
70+3(32) = 16625/166 = 0.15molesE. C4H10
4(12)+10(1) =5825/58 = 0.43molesAccording to the mole concept, there are 6.25 moles, 0.78 moles,0.32
moles, 0.15 moles, 0.43 moles.
What is a mole?Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons.Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.Number of moles=mass/molar mass
Thus, A. He,25/4 = 6.25 moles,B. O₂,25/32 = 0.78 moles,C. Al(OH)₃,25/78 = 0.32 moles,D. GaS₃,25/166 = 0.15 moles E. C₄H₁₀,25/58 = 0.43 moles.
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Which lifestyle is most likely to lead to infertility in a male ?
A man who works as a mechanic
A man who works as a computer programmer and sits at desk magority of the day
A semi professional athlete
A man who works for a company’s that applies pesticides to lawns
Answer:
The second on, A man who works as a computer programmer and sits at desk magority of the day.
Explanation:
Answer:
Explanation:
The only answer I can think as being possible is the last one. Pesticides are chemicals that go after unwanted animal life. They do not know that they should not attack human beings.
Infertility could very well be one of the side effects of a pesticide. There are others as well. Some pesticides go after the central nervous system (think mice and rats) and those are dangerous to use and to leave around.
The others all involve occupations that either require authentic abilities or mental astuteness. Neither should affect a man's ability to reproduce.
Which phrase describes an irregular galaxy?
O has a round shape
O contains many young stars
O has arms that extend from the center
O is larger than other types of galaxies
Answer: The answer would be B. contains many young stars.
Explanation:
There is very little new star formation in Irregular galaxies. Irregular galaxies have no particular shape and are smaller than other types of galaxies.
The irregular galaxy possess many young stars.
Irregular galaxyThey are the most unusual of galaxies.
They do not fit into either the elliptical or spiral galaxy categories.
They do not possess nice spiral arm, however, they do possess dark patches of dust and gas.
The irregular galaxies do not possess definite shape.
They comprise of several young stars as the extent of the formation of stars in irregular galaxies in brisk. They also do comprise old stars.
Thus, the correct statement is contains many young stars.
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