What is indicated by 'A' in the figure below? A. -VE B. +Ea C. -Ea D. +VE
Answer:
+VE
Explanation:
If we look at the reaction profile pictured in the question, we can easily identify A as the enthalpy of the reaction. The enthalpy of reaction (ΔHrxn) is usually defined as the difference between the total enthalpy (heat content) of the products of a reaction and the total enthalpy (heat content) of the reactants in that reaction.
Looking at the figure, we can see that the enthalpy of products is greater than the enthalpy of reactants, hence ∆Hrxn is positive as stated in the answer above.
Lavoisier developed a new theory of combustion that overturned the phlogiston theory. What measurements were central to his theory, and what key discovery did he make?
Answer:
Lavoiser proposed a theory in charge of writing the combustion correctly, denying the phlogiston.
Lavoiser said that combustion is carried out in a medium where there is oxygen, giving as a product water and carbon dioxide.
This combustion results in the decrease in the volume of the material that burns.
Furthermore lavoiser discovered the importance of oxygen in animal respiration.
Explanation:
Lavoisier argued that if or if the presence of oxygen must be present, it is an irreversible and spontaneous process.
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Which of the following is the best definition of a chemical property?
A. The solubility of salt.
B. The ability of gunpowder to explode.
C. The ability of something to undergo a change or reaction.
D. Something that can be observed or measured without changing the identity of the substance.
Answer:
The B. Is perfect match of a definition of chemical property.
Explanation:
The ability of gunpowder to explode.
The ability of gunpowder to explode is the best definition of a chemical property.
What is chemical property?The change of one type of matter into another type of matter and inability to change into the previous forms is called a chemical property. Examples of chemical properties include reactivity and heat of combustion.
So we can conclude that the ability of gunpowder to explode is the best definition of a chemical property.
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what is the question tag for Lynne speaks french and German
Answer:here is it...
Explanation:
The question tag for the statement "Lynne speaks French and German" would be "doesn't she?"
The question tag is a short question added to the end of a statement to turn it into a question and seek confirmation or agreement. It is usually formed by using an auxiliary verb opposite in polarity to the main verb in the statement.
In the given statement, "Lynne speaks French and German," the main verb is "speaks." Since the main verb is in the affirmative form, the question tag should use the negative form.
Therefore, we use the auxiliary verb "doesn't" (the negative form of "does") and add the pronoun "she" to match the subject of the statement.
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How do I know if CsBr in water is an acid, base or neutral? And how do I show it with a balanced equation
Answer:
Neutral
Explanation:
We can consider this salt as a neutral one. It can be prepared by a neutralization reaction between the base and the acid.
CsOH + HBr → H₂O + CsBr
As the two reactants are strong, the HBr as a strong acid, and the CsOH as a strong base, the ions are considered as: the weak conjugate acid and the weak conjugate base.
Br⁻ + H₂O ← HBr + OH⁻
Cs⁺ + H₂O ← CsOH + H⁺
They can not react to water, that's why the salt is neutral (similar as the NaCl)
pH = 7
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For the set of ionic compounds, CaSO4, CaCO3, Ca(OH)2, choose the correct characterization of their solubilities in water from the response list. Group of answer choices None of the three salts are soluble. All three salts are soluble. Two of the three salts are soluble. One of the three salts is soluble.
Answer:
None of the three salts are soluble.
Explanation:
According to the solubility rule, the carbonates and sulphates of group two elements are insoluble in water.
All three substances mentioned possess very low solubility in water and can be said to be slightly soluble in water. If we compare them with other ionic substances that dissolve readily in water, we can rightly say that they are insoluble in water.
Hence all three substances are insoluble in water.
Explain why human being is regarded as a complex machine.
Answer:
Well a human bein is a complex organism with pain and emotion.
There is a very very complex brain that recives and sends sis also faster than the eye can see.
Thats why when you touch a hot surface a lighting fast signal is sent from the hand to the brain and the brain sends a signal back to the hand to tell it what to do and this all happens a faster than a second.
A human is made out of millions, billions, trillions, and quadrillions if cells working together to perform special tasks like eating, walking, and talking.
Answer:
Humans are the only known species that are able to think as complexly as we do. For example, animals are not able to have thoughts about their thoughts. Animals are not able to ponder the existence of our universe, develop calculus, chemical solutions, etc. There are many other intelligent species- like chimpanzees and octopi. However, both of those species are limited in the type of communication, emotion, and complex thinking skills that they possess compared to human beings.
Explanation:
Which of the following is an acid-base neutralization reaction? (1 point) Sn + 2HBr yields SnBr2 + H2 HCl + KOH yields KCl + H2O 2AlCl3 + 3Ca(OH)2 yields 2Al(OH)3 + 3CaCl2 2C2H6 +7O2 yields 4CO2 + 6H2O
Answer:
Explanation:
Sn + 2HBr = SnBr₂ + H₂
Here HBr is an acid but Sn is not a base . It is a metal . So it is not an acid - base reaction .
HCl + KOH = KCl + H₂O
HCl is an acid and KOH is a base so it is an acid base reaction.
2AlCl₃ + 3Ca(OH)₂ = 2Al(OH)₃ + 3CaCl₂
It is an acid base reaction . It is so because aluminium hydroxide is a lewis acid and calcium hydroxide is a base . So it is an acid base reaction .
2C₂H₆ +7O₂ = 4CO₂ + 6H₂O
It is not an acid base reaction . It is actually an example of oxidation reaction in which ethane burns in oxygen to give carbon dioxide and water.
HELP ASAP! 50 POINTS! Which type of electromagnetic radiation has a longer wavelength than visible light? (4 points) Gamma rays Infrared radiation Ultraviolet radiation X‒rays
Answer:Infrared radiation
Explanation:just took the test
The electromagnetic radiation that has a longer wavelength than visible light is Infrared radiation.
The electromagnetic spectrum is an arrangement of of electromagnetic waves in order of increasing frequency and energy. We must note the longer the wavelength, the farther it appears towards the left in the electromagnetic spectrum.
The visible spectrum spans between 400 nm - 700 nm in the electromagnetic spectrum. The electromagnetic radiation that has a longer wavelength than visible light is Infrared radiation.
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According to periodic trend, which of the following most likely has the highest ionization energy?
Ca
Mn
Br
Zn
Answer:
Br
Explanation:
Ionization energy increases across a period.
All other elements are ahead in the period as compared to Br.
3.7500 x 104 + 9.7100 x 105
Answer: [tex]1409.55[/tex]
Remove the 0's from each decimal number
[tex]3.7500 ---> 3.75\\9.7100 ---> 9.71[/tex]
Multiply
[tex]3.75*104=390\\9.71*105=1019.55[/tex]
Add
[tex]930+1019.55=1409.55[/tex]
how much of the excess reactant remains unchanged?
how much N2 is formed? (in mol)
how much H2O is firmed? (in mol)
Answer:
1. The limiting reactant is H2O2.
2. The amount of excess reactant, N2H4 that remain unchanged is 11.15 moles.
3. 1.65 moles of N2.
4. 6.6 moles of H2O.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
N2H4 + 2H2O2 —> N2 + 4H2O
From the balanced equation above,
1 mole of N2H4 reacted with 2 moles of H2O2 to produce 1 mole of N2 and 4 moles of H2O.
1. Determination of the limiting reactant.
From the balanced equation above,
1 mole of N2H4 reacted with 2 moles of H2O2.
Therefore, 12.8 moles of N2H4 will react with = 12.8 x 2 = 25.6 moles of H2O2.
From the calculations made above, we can see that it will take a higher amount i.e 25.6 moles than what was given i.e 3.3 moles of H2O2 to react completely with 12.8 moles of N2H4.
Therefore, H2O2 is the limiting reactant and N2H4 is the excess reactant.
2. Determination of the excess reactant that remain unchanged.
The excess reactant is N2H4.
First, we shall determine the amount of the excess reactant that reacted. This is illustrated below:
From the balanced equation above,
1 mole of N2H4 reacted with 2 moles of H2O2.
Therefore, Xmol of N2H4 will react with 3.3 moles of H2O2 i.e
Xmol of N2H4 = (1 x 3.3)/2
Xmol of N2H4 = 1.65 moles
Therefore, 1.65 moles of N2H4 reacted.
Now, we shall determine the excess reactant that remain unchanged. This can be obtained as follow:
Amount of N2H4 given = 12.8 moles
Amount of N2H4 that reacted = 1.65 moles.
Amount of N2H4 that remain unchanged =?
Amount of N2H4 that remain unchanged = (Amount of N2H4 given) – (Amount of N2H4 that reacted = 1.65 moles)
Amount of N2H4 that remain unchanged = 12.8 – 1.65
Amount of N2H4 that remain unchanged = 11.15 moles.
3. Determination of the amount of N2 produced.
In this case, the limiting reactant will be used because it will give the maximum yield of N2 as all of it is used up in the reaction.
The limiting reactant is H2O2 and the amount of N2 produced can be obtained as follow:
From the balanced equation above,
2 moles of H2O2 reacted to produce 1 mole of N2.
Therefore, 3.3 moles of H2O2 will react to produce = (3.3 x 1)/2 = 1.65 moles of N2.
Therefore, 1.65 moles of N2 were obtained from the reaction.
4. Determination of the amount of H2O produced.
In this case, the limiting reactant will be used because it will give the maximum yield of H2O as all of it is used up in the reaction.
The limiting reactant is H2O2 and the amount of H2O produced can be obtained as follow:
From the balanced equation above,
2 moles of H2O2 reacted to produce 4 moles of H2O.
Therefore, 3.3 moles of H2O2 will react to produce = (3.3 x 4)/2 = 6.6 moles of H2O.
Therefore, 6.6 moles of H2O were produced from the reaction.
A student made the Lewis dot diagram of a compound as shown. Mg is written with two dots shown on its top. Cl is written on the right side of Mg. Cl has seven dots around it. An arrow is shown from one dot on Mg toward the vacant space around Cl. Another arrow is shown from the other dot on Mg toward the vacant space around Cl. On the top, the art title is written as Students Lewis Dot Model. What is the error in the Lewis dot diagram?
Answer:
The dots were not properly located and arrows are not used in Lewis structures
Explanation:
If we intend to write a Lewis structure for a compound, that lewis structure must consist of only dots. These dots actually show the valence electrons on the outermost shell of the molecule.
We do not involve arrows when writing dot electron structures for compounds. The valence electrons of magnesium ought not to be written together because they are not a lone pair, rather they are two unpaired electrons. The use of an arrow suggests a coordinate covalent bond which is not the case here.
The correct lewis structure for MgCl2 is shown in the image attached to this answer.
Answer: B is the answer took the test
Explanation: both electrons of Mg should be transferred to one O atom...
Naturally occurring magnesium exists as three isotopes. 78.70% is Mg-24 with a mass of 23.98504 amu, 10.13% is Mg-25 with a mass of 24.98584 amu, and 11.17% is Mg-26 with a mass of 25.98259 amu. What is the atomic mass of magnesium?
Answer:
The correct answer is 24.31 amu.
Explanation:
The formula for finding the average atomic mass = The sum of the percentage abundance of isotopes × the actual mass of isotopes
The average atomic mass = % abundance of Mg-24 × actual mass + % abundance of Mg-25 × its actual mass + % abundance of Mg-26 × its actual mass
Avg. Atomic mass = 0.7870 × 23.98504 + 0.1013 × 24.98584 + 0.1117 × 25.98259
Avg. atomic mass = 18.88 + 2.53 + 2.90 = 24.31 amu
The atomic mass of magnesium is 24.31 amu.
why solids do not undergo diffusion
Answer:
Solids do not undergo diffusion because it has a fixed structure (vibrates in a fixed position) and it also cannot be compressed.
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Given that the density of air is 14.4, then the vapour of sulphur IV oxide is A. 16 B. 32 C. 64 D. 128
Thank you.
Answer:
32
Explanation:
The vapour density of a gas is the number of times a given volume of gas or vapour is as heavy as the same volume of hydrogen at a particular temperature and pressure.
Vapour density = 2 × relative molecular mass of the gas or vapour
Relative molecular mass of SO2 = 32 + 2(16) = 64
Hence;
Vapour density of SO2 = 64/2
Vapour density of SO2 = 32
The specific heat capacity of a pure substance can be found by dividing the heat needed to change the temperature of a sample of the substance by the mass of the sample and by the change in temperature. The specific heat capacity of a certain substance has been measured to be 3.52 J/g °C. Suppose 420.0 g of the substance is heated until the temperature of the sample has changed by 43.8 °C.
Write an equation that will let you calculate the last Q that was needed for this temperature change. Your equation should contain only symbols. Be sure to define each symbol.
Answer:
The answers to your questions are given below.
Explanation:
Data obtained from the question include:
Mass (M) = 420.0 g
Temperature change (ΔT) = 43.8 °C
Specific heat capacity (C) = 3.52 J/g °C
Heat needed (Q) =...?
The heat needed for the temperature change can be obtained by using the following formula:
Q = MCΔT
Where:
Q is the heat needed measured in joule (J).
M is the mass of substance measured in grams (g)
C is the specific heat capacity of the substance with unit J/g °C.
ΔT is the temperature change measured in degree celsius (°C).
Thus, we can calculate the heat needed to change the temperature as follow:
Q = MCΔT
Q = 420 x 3.52 x 43.8
Q = 64753.92 J
Therefore, the heat needed to cause the temperature change is 64753.92 J
Which of the following statements about a chemical reaction is false? Group of answer choices The phases in a chemical reaction tell us the state of the reactants and the products. An individual coefficient, with no reactant or product, in a balanced equation is meaningless. The subscripts in a balanced equation tell us the number of atoms in a molecule.
Answer:
Option B
Explanation:
Let us go through each of the options individually.
option A.
he phases in a chemical reaction tell us the state of the reactants and the products.
This is true because phases representations such as s, l , g and q tells us the state of the reactants if they are in the solid or liquid or gaseous or aqueous state of matter respectively. So this is not our answer.
option B
An individual coefficient, with no reactant or product, in a balanced equation is meaningless.
This option is correct, because in every reaction, there must be the reactant and product present.
option C
The subscripts in a balanced equation tell us the number of atoms in a molecule.
This is correct. Consider the equation below;
2H₂ + O₂ --> 2H₂O
In the reactant phase, the subscripts tells us that we have just two atoms of oxygen present.
what is organic chemistry
Answer:
Organic chemistry
Explanation:
Organic chemistry is part of the chemistry that studies carbon compounds, which also use organic compounds, which have characteristics.
1. If I have 3 identical books that all have a length of 25cm, a
width of 15cm, and are 11cm tall, what would be the volume of
all 3 books?
Answer:
12,375 cm³
Explanation:
v=l×w×h
Since there are 3 books the equation would then be
v=3(l×w×h)
v=3(25×15×11)
v=3(4,125)
v=12,375 cm³
How are proteins carbohydrates and fats related to the discipline of chemistry
Answer:
Explanation:
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? All are chemical compounds. All are found in living things. All are needed for nutrition. All are found in non-living things.
The answer for this question would be A) All are chemical compounds.
The answer is All are chemical compounds
In the lab, Amanda has two solutions that contain alcohol and is mixing them with each other. She uses twice as much Solution A as Solution B. Solution A is 11% alcohol and Solution B is 18% alcohol. How many milliliters of Solution B does she use, if the resulting mixture has 320 milliliters of pure alcohol?
Answer:
1,103.47 milliliters
Explanation:
The total percentage of alcohol from solution A and solution B is 29. In a solution that is a mixture of solution A and B, the percentage of alcohol that would be contributed by solution A would be:--
11/29 x 100% = 37.93%
--while the percentage of alcohol that would be contributed by solution B would be:
18/29 x 100 = 62.07%
Hence, if a mixture of A and B has 320 milliliters of alcohol, the amount of alcohol contributed by B would be:
320 x 62.07/100 = 198.624 milliliters
Now, remember that solution B is 18% alcohol. This means that the 18% alcohol content of solution B is 198.624 milliliters. Thus, the total volume of solution B would be:
198.624 x 100/18 = 1,103.47 milliliters.
Therefore, the total milliliters of solution B Amanda used would be 1,103.47.
All the simple machines make work easier to do by changing the _____ or _____ of a force. A. size; type B. work; type C. size; direction D. type; direction
Answer:
C. size; direction
Explanation:
By definition, a machine is referred to any device that makes work easier. It takes force to do work, hence, work refers to the application of force over a particular distance. A machine aims at making the work easy by changing how it is done. Simple machines, which include: levers, pulleys, inclined planes etc. all carry out the same thing, which is to make work easier, by changing the size/magnitude and direction of the applied force.
A simple machine tends to change the size of the inputted force by increasing it over a shorter distance. The machine increases the force applied better than it can be done manually e.g. a plier and nutcracker increases/changes the applied force better than it can be done with bare hands.
Also, a simple machine can achieve making work easier by changing the direction at which the force is applied. The machine applies the force on the object in an opposite direction or contrary to the way it was manually applied.
Chemistry deals with all the following except: Select one: a. The composition of matter. b. The properties of matter. c. Our eating habits. d. The conversion of matter between various states.
Answer:
C. Our eating habits
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A baseball has a mass of 135 grams and a softball has a mass of 270 grams. In which of the following situations would they have the same momentum? The baseball and softball are thrown at the same speed in the same direction.
Answer:
The baseball is thrown twice as fast as the softball in the same direction.
Explanation:
you just got home from a run on a hot Atlanta afternoon. you grab a 1.00-liter bottle of water and drink three-quarters of it in one swig. How many moles of water did you consume?
Answer:
41.67 mol
Explanation:
1 Litre of water = 1000g
Mole = mass / molar mass
Mass of 1 L of water = 1000 g
Molar mass of water (H2O) :
(H = 1, O = 16)
H2O = (1 * 2) + 16 = (2 + 16) = 18g/mol
Amount of water consumed = (3/4) of 1 litre
= (3/4) * 1000g
= 750g
Therefore mass of water consumed = 750g
Mole = 750g / 18g/mol
Mole of water consumed = 41.6666
= 41.67 mol
name of the compound Br8P4
Answer:
4-phospho,Bromooctane
plz answer fast Which is not a crystalline allotrope of carbon? Select one: a. soot b. diamond c. graphite
Answer:
graphite
Explanation:
Graphite is opaque, a very good lubricant, a good conductor of electricity, and a thermal insulator. Allotropes of carbon are not limited to diamond and graphite, but also include buckyballs (fullerenes), amorphous carbon, glassy carbon, carbon nanofoam, nanotubes, and others.
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Why is graphite slippery when pressed? Select one: a. covalent bonds break b. hexagonal layers slide c. molecules of graphite slide
Answer:
hexagonal layers slide
Explanation:
The layers in graphite can slide over each other because the forces between them are weak. The delocalised electrons are free to move through the structure, so graphite can conduct electricity.This makes graphite slippery, so it is useful as a lubricant .
i think it's right
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