Answer:
Limiting factors are resources or other factors in the environment that can lower the population growth rate. Limiting factors include a low food supply and lack of space. Limiting factors can lower birth rates, increase death rates, or lead to emigration.
Explanation:
What could cause damage to your bike’s wheel?
A) twisting the tube around the wheel
B) riding your bike with a flat tire
C) air escaping from the tube
D) under-inflating the tire
Explain how temperature can affect the speed of reaction. Give an example.
Answer:
Chemical reactions proceed at different rates. The factors that affect reaction rates are:
surface area of a solid reactant
concentration or pressure of a reactant
temperature
nature of the reactants
presence/absence of a catalyst.
A change in one or more of these factors may alter the rate of a reaction. In this lesson, you will define these factors, and describe and predict their effects on reaction rates.
Surface Area
Surface area is the exposed matter of a solid substance.
Imagine that you are holding a perfect cube of magnesium. The surface area is the sum of the area of all six sides of the cube. The surface area of the cube can be increased by dividing the cube into smaller cubes. Surface area is maximized when a single large cube is crushed to fine powder.
The rate of reaction of a solid substance is related to its surface area. In a reaction between a solid and an aqueous/liquid/gas species, increasing the surface area of the solid-phase reactant increases the number of collisions per second and therefore increases the reaction rate.
In a reaction between magnesium metal and hydrochloric acid, magnesium atoms must collide with the hydrogen ions. When the magnesium atoms form one big lump...
The concentration of a gas is a function of the pressure on the gas. Increasing the pressure of a gas is exactly the same as increasing its concentration. If you have a certain number of gas molecules, you can increase the pressure by forcing them into a smaller volume.
Under higher pressure or at a higher concentration, gas molecules collide more frequently and react at a faster rate. Conversely, increasing the volume of a gas decreases pressure which in turn decreases the collision frequency and thus reduces the reaction rate.
It is important to note however that there are reactions involving gases in which a pressure change does not affect the reaction rate. For this reason, the rates of reactions involving gases have to be determined by experiment.
Also note that solids and liquids are not affected by pressure changes.
Need a good analogy for the effect of concentration on the rate of a chemical reaction?
Temperature
With the exception of some precipitation reactions involving ionic compounds in solution, just about all chemical reactions take place at a faster rate at higher temperatures. The question is why?
Temperature (in Kelvin degrees) is proportional to the kinetic energy of the particles in a substance. For example, if the Kelvin temperature of a substance is doubled, then the average kinetic energy of the particles in that substance is doubled.
At higher temperatures, particles collide more frequently and with greater intensity.
Here's an analogy.
Imagine that you are baby-sitting a bunch of 6 year olds. You put them in a yard and you let them run around. Every now and then a couple of kids will run into each other. Now imagine that you decide to feed them some sugar. What happens? They run around faster and of course there are many more collisions. Not only that, the collisions are likely to be a lot harder/more intense.
Now, let's look at the effect graphically. Recall that in any sample of matter (the example we used previously was a gas), individual particles have different kinetic energies. Some are moving fast some are moving slowly, and most are moving at some intermediate speed.
Increasing the temperature by say 10°C causes some of the intermediate speed molecules to move faster. The result is more molecules with sufficient kinetic energy to form an activated complex upon collision!
Now consider the relationship between threshold kinetic energy and activation energy. Threshold kinetic energy is the minimum amount of energy required for colliding particles to react - it is the equivalent of activation energy or the minimum potential energy gain required to form an activated complex.
As you can see on the graph, a small increase in temperature can double the number of molecules with the threshold kinetic energy.
Thus there are two effects of increasing temperature: greater collision intensity and more frequent collisions.
A general rule is that a 10°C temperature increase can double a reaction rate. It turns out that the increase in the reaction rate is mainly a function of the more intense collisions. Increased collision frequency is not as significant a factor.
Explanation:
A gas at 155 Kpa and 25 degrees celsius has a volume of 1 L. The pressure increases to 605 kPa as the temperature is raised to 125 degrees Celsius what is the new volume?
Answer:
The answer to your question is V2 = 0.34 l
Explanation:
Data
Pressure 1 = P1 = 155 kPa
Temperature 1 = T1 = 25°C = 298°K
Volume 1 = V1 = 1 l
Pressure 2 = P2 = 605 kPa
Temperature 2 = T2 = 125°C = 398°K
Volume 2 = V2 = ?
Process
To solve this problem use the Combined gas law.
P1V1/T1 = P2V2/T2
-Solve for V2
V2 = P1V1T2 / T1P2
-Substitution
V2 = (155)(1)(398) / (298)(605)
-Simplification
V2 = 61690 / 180290
-Result
V2 = 0.34 l
What is the change in entropy that occurs in the system when 1.00 mol of methanol (ch3oh) vaporizes from a liquid to a gas at its boiling point (64.6 ∘c)? for methanol, δhvap=35.21kj/mol. what is the change in entropy that occurs in the system when 1.00 of methanol () vaporizes from a liquid to a gas at its boiling point (64.6 )? for methanol, . -545 j/k 104 j/k -104 j/k 545 j/k?
Answer:
104 J/K
Explanation:
First, we have to calculate the heat (Q) involved in the vaporization of 1.00 mol of methanol.
Q = n × ΔH°vap
Q = 1.00 mol × 35.21 kJ/mol = 35.2 kJ
Then, we have to convert the boiling point to Kelvin.
K = °C + 273.15
K = 64.6 + 273.15 = 337.8 K
Finally, we calculate the change in the entropy associated with this process.
ΔS = Q/T
ΔS = 35.2 kJ/337.8 K = 0.104 kJ/K = 104 J/K
A solution is prepared by dissolving 15.0 g of NH3 in 250 g of water. The density of the resulting solution is 0.974 g/mL. The mole fraction of NH3 in the solution is _____.A) 16.8B) 0.940C) 0.0597D) 0.922E) 0.0640
Answer:
Mole fraction of [tex]NH_{3}[/tex] in solution is 0.0597.
Explanation:
Molar mass of [tex]NH_{3}[/tex] = 17.031 g/mol
Molar mass of [tex]H_{2}O[/tex] = 18.015 g/mol
No. of moles = (mass)/(molar mass)
So, 15.0 g of [tex]NH_{3}[/tex] = [tex]\frac{15.0}{17.031}[/tex] moles of [tex]NH_{3}[/tex] = 0.8807 moles of [tex]NH_{3}[/tex]
250 g of [tex]H_{2}O[/tex] = [tex]\frac{250}{18.015}[/tex] moles of [tex]H_{2}O[/tex] = 13.88 moles of [tex]H_{2}O[/tex]
So, Mole fraction of [tex]NH_{3}[/tex] in the solution = (no.of moles of [tex]NH_{3}[/tex] )/(total no. of moles) = [tex]\frac{0.8807}{0.8807+13.88}[/tex] = 0.0597
Hence, mole fraction of [tex]NH_{3}[/tex] in solution is 0.0597.
Which 1.0 M solution has the lowest pH?
Answer: nitric acid
Explanation:
The solution with the lowest pH would mean that it is an acid, specifically a strong acid which completely dissociates into ions in aqueous solution. The answer it is nitric acid (HCl) that will have the lowest pH because it is the only strong acid in the group
Extend your thinking: Why do you think the temperature does not change much during a phase change? If possible, discuss your answer with your classmates and teacher.
Answer:
The rate of temperature change does not stay constant and decreases over time because the temperature difference decreases over time.
Explanation:
The temperature difference is due to Thermal Equilibrium
Dissolving potassium chlorate (KClO3) is even more endothermic than potassium chloride.
Your task is to determine how many grams of potassium chlorate you would have to add to 100 mL of water to produce the same temperature change as 5 grams of KCl.
Answer:
The mass of KClO₃ that will absorb the same heat as 5 g of KCl is 3.424 g
Explanation:
Here we have
Heat of solution of KClO₃ = + 41.38 kJ/mol.
Heat of solution of KCl (+17.24 kJ/mol)
Therefore, 1 mole of KCl absorbs +17.24 kJ during dissolution
Molar mass of KCl = 74.5513 g/mol
Molar mass of KClO₃ = 122.55 g/mol
74.5513 g of KCl absorbs +17.24 kJ during dissolution, therefore, 5 g will absorb
[tex]\frac{17.24}{74.5513 } \times 5 \, \, kJ \, or \, 1.156 \, kJ[/tex]
Therefore the amount of KClO₃ to be dissolved to absorb 1.156 kJ of energy is given by
122.55 g of KClO₃ absorbs + 41.38 kJ, therefore,
[tex]\frac{1.156}{41.38} \times 122.55 \, g = 3.424 \, g[/tex]
Therefore the mass of KClO₃ that will absorb the same heat as 5 g of KCl = 3.424 g.
If both potassium chlorate and potassium chloride had the same specific heat, you would need 5 grams of potassium chlorate to produce the same temperature change in 100 mL of water. This is a simplified scenario and in real-life, there would be slight differences.
Explanation:To answer this question, we need to assume that potassium chlorate and potassium chloride have the same specific heat and that the water's heat capacity is much greater than either salt. Therefore, the amount of heat energy required to increase the temperature of water is the same for both salts. If 5 grams of potassium chloride produce the same temperature change, an equal amount of heat energy would be required for the potassium chlorate. Hence, you would need 5 grams of potassium chlorate to produce the same temperature change.
Please understand that this is a simplified explanation. In a real-life situation, there would be some differences due to the different chemistry of the salts.
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A tiger cub has a pattern of stripes on its fur that is similar to that of its parents. Where are the instructions stored that provide information for a tiger’s fur pattern?
Answer:
On genes within chromosomes
Explanation:
-The fur pattern is a genetic trait whose instruction is carried in the DNA's base sequence.
-These instructions are organized into genes and each gene is only responsble for the making of a functional product.
-Hence, the instructions are stored on genes within chromosomes.
A branch of science which deals with a living being is called biology.
The correct answer is DNA.
The DNA stands for Deoxyribonucleic acid. it contains all the information about the parents.
The transfer of character from one generation to another is called inheritance.
In this case which is mentioned in the question, the stripes character is a transfer from the parent to the offspring in the form of a gamete cell. Gamete has all the information of the parent which shows the character after maturing.
Hence, the correct answer is DNA stored in the gamete.
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When focusing on nearby objects, the highlighted structure: __________.
1. becomes flatter
2. gains fluid from surrounding aqueous humor
3. does not change shape
4. becomes rounder
Answer:
The correct option is;
4. becomes rounder
Explanation:
The ciliary muscles in the eye controls the shape of the lens when looking at objects located at different positions. A close by object such as a book that appears large and the eye has to capture the light from wide angles and therefore the lens is made more rounded to enable the light rays to be focused for viewing.
Similarly when looking at far objects, the lens changes to become more planar.
Accommodation is the term used to describe the ability of the eye lens to change its focus and shape.
What is the dropping of a sediment called
Answer:Deposition is the dropping of sediment by wind, water, ice, or gravity.
Explanation:
When thermal energy is added to a substance, its temperature increases, which can change its state from solid to liquid
Answer:
The dropping of a sediment is called deposition.Which solution is the most concentrated?
you have a picture so i can see it
Choose all of the correct statements concerning acids and bases.
Addition of base into the water increase hydronium ion concentration of the solution is a false statement other 4 are correct.
Explanation:
An acid is referred to as substance that is denoting hydrogen ion. A base is referred to as a substance that is accepting hydrogen ions. Certain examples of acids are sulphuric acid, citric acid and certain examples of bases are ammonia as well as bleach. The difference that occur between the acid and the base is due to its pH. Acids have the ability to neutralize the base.Answer: 1, 2 and 5
Explanation:
did usatestprep
How many moles are in 4.20 g of SO2?
Answer:
0.066 mole SO₂
Explanation:
moles = mass in grams / formula weight
= 4.2g/64g/mol = 0.066 mole SO₂
It takes 86 joules of energy to raise a box 2 meters using the pulley setup shown above.
Without the pulley, the box can be raised 2 meters using only 82 joules of energy. What could explain this 4-joule difference?
A.
When raising the box using the pulley, 4 joules of mechanical energy are broken down into protons, neutrons, and electrons.
B.
When raising the box using the pulley, 4 joules of mechanical energy are transformed into water.
C.
When raising the box using the pulley, 4 joules of mechanical energy are converted into heat energy due to friction.
D.
When raising the box using the pulley, 4 joules of mechanical energy are destroyed.
Answer:
the correct answer is c
Answer:
The answer is C, when raising the box using the pulley, 4 joules of mechanical energy are converted into heat energy due to friction. :)
Explanation:
Define dissolve in your own words
Answer:
Dissolve: to terminate a union of multiple members actively, as by disbanding
Bromelain works by breaking the enzymes that cause browning into smaller molecules. Explain how the reaction that breaks up the enzymes occurs.
Bromelain separates the amino acids in the enzymes that cause browning by breaking the peptide bonds. The pH of a solution determines the charge of certain R groups.
Amino acids are defined as the substances which are considered to be the monomers of proteins.Every amino acid has the same structure consisting of a central carbon which is bonded to an amino group , carboxyl group and a hydrogen.
Each amino acid also has another atom or a group of atoms bonded to the alpha carbon which are also known as the R group or the variable group of the side chain.There are 20 common amino acids present in natural proteins and each amino acid has the same backbone.
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uiz: Types of Chemical Reactions 11:Chemical Reactions 10. In a double-replacement reaction, _____. the reactants are usually a metal and a nonmetal one of the reactants is often water the reactants are generally two ionic compounds in aqueous solution energy in the form of heat or light is often produced
complete question:
In a double-replacement reaction , _____.
a. the reactants are usually a metal and a nonmetal
b.one of the reactants is often water the reactants
c. the reactants are generally two ionic compounds in aqueous solution
d. energy in the form of heat or light is often produced
Answer:
c. the reactants are generally two ionic compounds in aqueous solution
Explanation:
A double replacement reaction is a kind of chemical reaction where two compounds reacts and the cations and anions of the reacting compound exchange places to form two new compound or products.
The double replacement reaction is also known as a double displacement reaction. A precipitate is usually form in this kind of reaction. The two reactant that takes place in this reaction are ionic in nature. Example of a double replacement reaction is the reaction between silver nitrate and sodium chloride to precipitate silver chloride and produce a soluble sodium nitrate.
AgNO3 + NaCl → AgCl + NaNO3 .
The sodium cation replace Ag in it compound while Ag replace Na in it compound. The anions also exchange places too.
A gas that has a pressure of 2 atm and
a volume of 10 L. What would be the
new volume if the pressure was
changed to 1 atm?
Answer:
The answer to your question is 20 liters
Explanation:
Data
Pressure 1 = P1 = 2 atm
Volume 1 = V1 = 10 l
Pressure 2 = P2 = 1 atm
Volume 2 = V2 = ?
Process
To solve this problem use Boyle's law
P1V1 = P2V2
-Solve for V2
V2 = P1V1/P2
-Substitution
V2 = (2 x 10)/1
-Simplification
V2 = 20/1
-Result
V2 = 20 l
a reseacher observes a vehicle with a inital velocity of 14m/s. the vehicle accelerates uniformly with a acceleration of 3 m/s2. after 6 seconds ,what is the velocity of the vehicle?
Answer:
32m/s
Explanation:
the explanation is in the picture
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Examine this reaction:
starch⟶amylasedisaccharides⟶disaccharidasemonosaccharides
If there is the normal amount of amylase present but less disaccharidase than usual, which of the following would most likely happen?
No starch could be broken down to disaccharides.
There would be less disaccharide and less monosaccharide produced.
The normal amount of disaccharide would be produced, but fewer monosaccharides would be produced.
There would be no overall impact because the normal amount of amylase is present.
Answer:
The normal amount of disaccharide would be produced, but fewer monosaccharides would be produced.
Explanation:
The first reaction, the conversion of starch into disaccharides, is catalyzed by the enzyme amylase. Since amylase is present in a normal amount, a normal amount of disaccharides will be produced.
In the second reaction, these disaccharides will be transformed into monosaccharides by a disaccharidase. However, since there is less disaccharidase, there will be fewer monosaccharides produced than if it was a normal amount of amylase.
Final answer:
If there is a normal amount of amylase but less disaccharidase than usual, the normal amount of disaccharide would be produced, but fewer monosaccharides would result from the reaction.
Explanation:
When examining the reaction starch → amylase → disaccharides → disaccharidase → monosaccharides, the presence of a normal amount of amylase means that starch can be broken down into disaccharides effectively. However, with less disaccharidase than usual, fewer monosaccharides would be produced from the disaccharides. The normal amount of disaccharide produced by amylase would not change, but since disaccharidase is responsible for the breakdown of disaccharides into monosaccharides, a deficiency in this enzyme means the reaction would be incomplete, leading to less monosaccharides being produced.
2. A 0.5 kg tennis ball has speed of 15m/s. what is the kinetic energy of tennis?
Explanation:
Given
mass (m) = 0.5 kg
velocity (v) = 15 m/s
Now
Kinetic energy
= 1/2 *m*v²
= 1/2 * 0.5 * 12²
= 0.5 *0.5 * 144
= 36 joule
hope it will help
Consider the following errors that could be made when running TLC. Indicate what should be done to correct the error. a. A two-component mixture containing 1-octene and 1, 4-dimethylbenzene gave only one spot with an Rf value of 0.95. The solvent used was acetone.
Final answer:
To correct a high Rf value of 0.95 in TLC, decrease the polarity of the mobile phase by using a less polar solvent and ensure the sample is not too concentrated for improved separation and accurate Rf values.
Explanation:
When running Thin Layer Chromatography (TLC), a high Rf value of 0.95 implies that the sample has moved almost as far as the solvent front, suggesting that the mobile phase is too polar. To correct this and achieve better separation, the polarity of the mobile phase should be decreased.
Using a less polar solvent, such as a mixture of hexanes and ethyl acetate, instead of pure acetone might provide better separation of the components 1-octene and 1, 4-dimethylbenzene.
Additionally, ensuring that the samples are not too concentrated can lead to more accurate Rf values and better spot definition. A correctly run TLC should show the desired component with an Rf around 0.35, separated from other spots by at least 0.2 Rf units.
Calculate delta s ,delta s total when the volume of 123 g CO initially at 298K and 1 bar increased by a factor of four in (a) an adiabatic reversible expansion
Final answer:
The change in entropy (ΔS) for an ideal gas during a reversible adiabatic process is zero because no heat is exchanged with the surroundings. Hence, the total change in entropy (ΔS_total) is also zero for such a process.
Explanation:
To calculate the change in entropy (ΔS) of 123 g of carbon monoxide (CO) during an adiabatic reversible expansion, one should use the thermodynamic definition of entropy. However, since no specific heat is provided for CO, and the problem implies an ideal gas behavior, usually entropy change for an ideal gas in an adiabatic process is zero because no heat is transferred into or out of the system (ΔQ = 0). In adiabatic processes, all expansion work is done at the expense of the internal energy of the gas, and since entropy is a function of heat exchange at a given temperature, the net change in entropy for the gas in such a process is zero.
For the second part of the question, computing the total entropy change ΔS_total during the expansion would typically require considering the surroundings as well. In a truly adiabatic and reversible expansion, there is no heat exchange with the surroundings, thus no change in the entropy of the surroundings, and the total entropy change would likewise be zero. In the real world or in irreversible processes, ΔS_total might be different, but these require additional information.
Fluorine and Nitrogen react to form a covalent molecule. Which best describes the molecule they will make?
There are 3 Nitrogens and 1 Fluorine. Nitrogen will be the central atom.
There are 3 Fluorines and 1 Nitrogen. Fluorine will be the central atom.
There are 3 Nitrogens and 1 Fluorine. Fluorine will be the central atom.
There are 3 Fluorines and 1 Nitrogen. Nitrogen will be the central atom.
Final answer:
Fluorine and nitrogen react to form a molecule where nitrogen is the central atom, bonded to three fluorine atoms. This is due to nitrogen's ability to form multiple bonds and its relative electronegativity compared to fluorine.
Explanation:
The correct description of the molecule formed by fluorine and nitrogen is: There are 3 Fluorines and 1 Nitrogen. Nitrogen will be the central atom. In molecules where nitrogen is combined with halogens like fluorine, nitrogen often serves as the central atom due to its capacity to form multiple bonds and its comparably lower electronegativity than halogens. This is consistent with the general rule that less electronegative atoms tend to be central in molecular structures. For instance, nitrogen (N) has five valence electrons and can share these electrons to form covalent bonds, whereas fluorine (F), being more electronegative, typically forms single bonds and is often found as a terminal atom.
If a sample gas is collected over water. The atmospheric pressure is 778 mm and the temperature is 30°C. If the vapor pressure of water at 30 C is 31.8 mm, what is the pressure of the gas?
Answer:
P = 746.2 mmHg or 0.9818 atm
Explanation:
First, we have a sample gas (This can be hydrogen, argon, nitrogen or any other gas) that was collected with a pressure of 778 mmHg. We also know the vapor pressure which is 31.8 mmHg. To get the pressure that the gas is exerting, we can assume that the atmospherical pressure is the total pressure of the whole system. Therefore we can use the following expression:
Pt = Pw + Pg (1)
Where:
Pt: total pressure
Pw: water pressure
Pg: gas pressure
From (1) we can solve for the gas pressure and have:
Pg = Pt - Pw
Replacing the data we have:
Pg = 778 - 31.8
Pg = 746.2 mmHgThis would be the pressure of the gasIf you want this value in atm, you should divide it by 760 mmHg (Conversion from mmHg to atm):
Pg = 746.2 / 760
Pg = 0.9818 atmchemical or physical change? and what made you think such?
Answer:
it's a chemical change and an electrolytic reaction
Which equation represents a single replacement reaction that can occur?
A. 2 Cu + FeSO4 → Fe + Cu2SO4
B. Ag + KNO3 → K+ AgNO3
C. l2 + MgCl2 → Cl2 + Mgl2
D. K+ NaF → KF + 2 Na
HELP!!
Which claim about how temperature relates to heat is correct?
A Temperature is a measure of the heat of an object.
B Heat causes a change in the temperature of an object.
C Raising the temperature causes the heat of an object to increase.
D Temperature and heat are two different ways to measure the same thing.
Answer:
raising the temperature increases heat in the object... heat is a form of energy that is induced in an object by raising temperature
C
Explanation:
raising temperature causes the heat of an object to increase
Select the compounds from the list below which are insoluble in water
HCl, NH3, NaClO3, BaSO4, AgNO3, PbCl2, Cu2O, CuSO4, Pb(C2H3O2), AgBr
Answer:
Insoluble in water:
BaSO4PbCl2Cu2OAgBrExplanation:
Water turns out to be a good solvent for ionic substances, or in general, polarized covalent substances. On the other hand, it is not a good solvent for non-polar substances, these being the vast majority of covalent substances.