Answer:
Human ears can hear sound waves that vibrate in the range from about 20 times a second (a deep rumbling noise) to about 20,000 times a second (a high-pitched whistling). (Children can generally hear higher-pitched sounds than their parents, because our ability to hear high frequencies gets worse as we get older.) Speaking more scientifically, we could say that the sounds we can perceive have a frequency ranging from 20–20,000 hertz (Hz). A hertz is a measurement of how often something vibrates and 1 Hz is equal to one vibration each second. The human voice makes sounds ranging from a few hundred hertz to a few thousand hertz.
Suppose you could somehow hit a drum-skin so often that it vibrated more than 20,000 times per second. You might be able to see the skin vibrating (just), but you certainly couldn't hear it. No matter how hard you hit the drum, you wouldn't hear a sound. The drum would still be transmitting sound waves, but your ears wouldn't be able to recognize them. Bats, dogs, dolphins, and moths might well hear them, however. Sounds this like, with frequencies beyond the range of human hearing, are examples of ultrasound.
Ultrasound is sound or other vibrations having an ultrasonic frequency, particularly as used in medical imaging. Also, Infrasound is sound waves with frequencies below the lower limit of human audibility
which are examples of dynamic equilibrium
Answer:Dynamic Equilibrium Examples. Any reaction will be in dynamic equilibrium if it's reversible and the rates of the forward and reverse reactions are equal. For example, say that you prepare a solution that is saturated with an aqueous solution of NaCl.
Explanation:
Answer:
2,4,5
Explanation:
on edg
which statement defines activation energy?
Answer:
The statement which defines activation energy is that it is the difference between reactant energy and maximum energy.J
Explanation:
A reaction that does not have activation energy will not take place at all.
Answer:
c
Explanation:
The following question appears on a quiz: "You fill a tank with gas at 60°C to 100 kPa and seal it. You decrease the temperature to 10°C but keep the volume constant. What happens to the pressure?" A student answers that the new pressure will be 17 kPa. Which of the following explanations is true?
The student did not solve for the correct parameter, and the answer should be 50 kPa.
The student did not solve for the correct parameter, and the answer should be 600 kPa.
The student did not work with absolute temperatures, and the answer should be 85 kPa.
The student did not work with absolute temperatures, and the answer should be 888 kPa.
Answer:
The student did not work with absolute temperatures, and the answer should be 85 kPa.
Explanation:
We can use the general law of ideal gas: PV = nRT.where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
If n and V are constant, and have two different values of P and T:P₁T₂ = P₂T₁
P₁ = 100.0 kPa, T₁ = 60.0°C + 273 = 333.0 K.
P₂ = ??? kPa, T₂ = 10.0°C + 273 = 283.0 K.
∴ P₂ = P₁T₂/T₁ = (100.0 kPa)(283.0 K)/(333.0 K) = 84.98 kPa ≅ 85.0 kPa.
So, the right choice is:
The student did not work with absolute temperatures, and the answer should be 85 kPa.
The student did not work with absolute temperatures, and the answer should be 85 kPa.
Explanation:
We can use the general law of ideal gas: PV = nRT.
where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
If n and V are constant, and have two different values of P and T:
P₁T₂ = P₂T₁
P₁ = 100.0 kPa, T₁ = 60.0°C + 273 = 333.0 K.
P₂ = ??? kPa, T₂ = 10.0°C + 273 = 283.0 K.
∴ P₂ = P₁T₂/T₁ = (100.0 kPa)(283.0 K)/(333.0 K) = 84.98 kPa ≅ 85.0 kPa.
So, the right choice is:
The student did not work with absolute temperatures, and the answer should be 85 kPa.
Niagara Falls is a good example of
A.kinetic energy being converted into potential
B.potential energy being converted into kinetic energy
C.energy being lost
D.energy being created
Which one ?^
B. Potential energy being converted into kinetic energy. Hope this helps!
The second answer choice
To which mineral group do most of the rocks in Earths crust belong?
Answer: silicate
Explanation:
Answer:
Silicates
Explanation:
About 90 percent of the earth's crust is composed from silicate class of minerals. They are the various compounds of silicon and other chemical elements. Quartz and feldspar are the two most common types of silicate types that are found in Earth’s crust. Mica and olivine, which are the lesser concentrates of silicates are also found abundantly in the earth's crust.
which of the following is not a base?
A. bleach
B.toothpaste
C.shampoo
D.orange
Answer:
c. shampoo
Explanation:
What is the mass of 2.30 ×1022 molecules of NaOH (Molar mass = 40.0 g/mol)?
Answer:
1.52 g NaOH
Explanation:
The molar mass M is a physical property defined as the mass of a given substance (chemical element or chemical compound) divided by the amount of substance.
Molar mass of NaOH is 40.0 g/mol
40.0 g/mol contains 6.022 × 10²³ molecules
∴ 2.30 × 10²² molecules will contain (2.30 × 10²²) * (40.0)/6.022× 10²³
= 1.52 g NaOH
How many atoms are in 8.1 moles of oxygen? And how do you know?
Answer:
4.88 x 10²⁴atoms
Explanation:
Given parameters:
Number of moles of oxygen = 8.1moles
Problem:
To find the number of atoms in 8.1moles of oxygen.
Method in solving the problem:
We know that a mole of a substance contains Avogadro’s number of particles which is 6.02 x 10²³
The particles can be molecules, atoms, etc.
Solution:
From the concept of mole,
Number of atoms =
number of moles x 6.02 x 10²³
Number of atoms = 8.1 x 6.02 x 10²³
Number of
atoms of oxygen = 48.8 x 10²³ atoms
= 4.88 x 10²⁴atoms
Consider the following three-step representation of a reaction mechanism.
Step 1: A + B --> AB (fast) and the rate = k[A][B]
Step 2: AB + B --> AB2 (slow) and the rate = k[AB][B]
Step 3: AB2 + B --> AB3 (fast) and the rate = k[AB2][B]
Overall: A + 3B --> AB3 and the rate = k[A][B]2
Which explains why the rate law for the overall equation is not the same as the rate equation for the rate-determining step?
A; The fastest step determines the overall rate law.
B: The overall rate law is determined from the balanced equation.
C: AB is an intermediate; therefore the rate law is determined from the reactants in the previous step.
D: B is an intermediate; therefore the rate law is determined from the reactants in the previous step.
Answer:
The answer is C. AB is an intermediate; therefore the rate law is determined from the reactants in the previous step.
I just took the test and C. was correct. Please mark me as brainliest!
Answer: C: AB is an intermediate; therefore the rate law is determined from the reactants in the previous step.
Explanation: : Rate law is usually determined from the slowest step of the reaction mechanism.
Thus as we can see that the reaction which is slow has AB as its intermediate, rate law can be determined from the same.
Moreover , we can see that the overall rate law is very different from the rat law determined from the slowest step.
HELP ME WITH THIS 60 POINTS,5-STAR RATING, AN THANKS AND MARKED AS BRANLIEST.
Susan Wondered why she heard less crickets in the fall than during the summer.She decided to investigate how temperature affects the chirping of crickets.Susan hypothesized that if the temperature is decreased, then the number of chirps would decrease, then the number of chirps would decrease.She took 10 crickets and 10 containers and place a cricket in each one.She recorded the number of chirps each cricket made in one minute at a room temperature.Susan gave all the crickets the same amount of food, water,and same type of container.
Independed Variable:
dependent variable:
Hypothesis:
constants:
repeated trails:
control:
Answer:
Independed Variable:
food, water, container
dependent variable:
temperature
Hypothesis:
That there are less chirps if temperature is lower
constants:
food, water, container
repeated trials:
10 crickets and 10 containers, 10x accurate than using 1 and 1
control:
Crickets and containers
At 0 degrees Celsius, a gas occupies 22.4L. How hot must the gas be in celcius to reach a volume of 25.0L
Answer:
31.7 °C
Explanation:
Charles law states that for volume of a gas is directly proportional to the absolute temperature for a fixed amount of gas at constant pressure
we can use the following equation
V1/T1 = V2/T2
where V1 is volume and T1 is temperature at first instance
V2 is volume and T2 is temperature at second instance
temperature should be in kelvin scale
T1 - 0 °C + 273 = 273 K
substituting the values in the equation
22.4 L / 273 K = 25.0 L / T2
T2 = 304.7 K
temperature in celcius is - 304.7 K - 273 = 31.7 °C
the gas must be 31.7 °C to reach a volume of 25.0 L
What does the octane rating of gasoline tell you about the gasoline? Where can you see the octane rating of the gasoline you buy?
Answer:
Explanation:
The Octane rating is the % Octane in the grade that you are buying. In the United States, the octane rating of the cheapest gas is around 85%. In Canada, it is about 87% which in the states is the mid grade.
As soon as you take out the nozzle from its container, you have to press a large colored button to pick the octane rating. The button is so large and the writing is so limited, that you cannot miss the grade. Usually they are put together on the pump like this
87 89 91
I've given you the Canadian numbers; I'm not sure what they are in the US, but the numbers I've used are pretty close.
What is the overall order of reaction for this rate law: Rate = k ? A. zero B. first C. second D. third
Answer: hey plato buddie, the answer is A! zero
Explanation:
Answer : The overall order of reaction is, (A) zero order reaction.
Explanation :
Rate of reaction : It is defined as the rate of change in concentration of reactant or product with respect to time.
Order of reaction : It is defined as the sum of the exponents or powers to which the molar concentration in the rate law equation are raised to express the observed rate of reaction. It depends on the power of concentration of reactant.
As per question, the given rate expression is,
[tex]Rate=k[/tex]
From this expression we conclude that there is no power of concentration of reactant. That means, it is a zero order reaction.
Hence, the rate order of reaction is, zero order reaction.
When 2 grams of powdered lead (IV) oxide was added to 100 cm3 of hydrogen peroxide, water and oxygen were produced. Lead (IV) oxide was not used up in the reaction. Based on the information, which of the following is likely to decrease the rate of formation of the products?
Replacing the powdered lead oxide with its large crystals
Removing lead (IV) oxide from the reaction mixture
Using 50 cm3 of hydrogen peroxide
Using 1.0 gram of lead (IV) oxide
Answer:
The right answer is:
Replacing the powdered lead oxide with its large crystals
Removing lead (IV) oxide from the reaction mixture
Using 1.0 gram of lead (IV) oxide
Explanation:
Based on the given information this reaction is the catalytic decomposition of H₂O₂ into water and oxygen using Lead (IV) oxide as a catalyst.
The catalyst surface area is directly proportional to the reaction rate So, Replacing the powdered lead oxide with its large crystals would decrease the reaction rate due to the has larger surface area than its large crystals.2. Also, Removing lead (IV) oxide from the reaction mixture the reaction rate decreased because as the catalyst is removed.
3. Using 50 cm³ of hydrogen peroxide doesn't affect the rate because the concentration of the reactant doesn't change.
4. Using 1.0 gram of lead (IV) oxide would decrease the reaction rate because the amount of catalyst decreased
So, The right answer is:
Replacing the powdered lead oxide with its large crystals
Removing lead (IV) oxide from the reaction mixture
Using 1.0 gram of lead (IV) oxide
25) If an object’s density is greater than 1.00 g/mL, it will ______________ in water.
A) Sink
B) Float
__________________________________________
If an object’s density is less than 1.00 g/mL, it will ______________ in water.
A) Sink
B) Float
_______________________________________________________
26) What is the density of a rock if it has a mass of 50 g and a volume of 10 mL? (You must show your work!)
Answer:
1- Option A = Sink
2- Option B = Float
Explanation:
1- If an object’s density is greater than 1.00 g/mL, it will sink in water.
For example, the density of aluminum is 2.7g/cm³. That is why it will sink in water.
2- If an object’s density is less than 1.00 g/mL, it will float in water.
For example, the density of oak is 0.7 g/cm³. That is why oak will float in water.
3- Given data:
Mass, m = 50 g
Volume, v = 10 cm3 ( 1ml = 1cm3)
Formula of density :
Density = mass/ volume
d = m/v
d = 50g/10cm3
d = 5 g/cm3
How are acids and bases similar and different
Answer & Explanation:
Similarities:
Both acids and bases are electrolytes which means that they're good conductors of electricity. Acids and bases both produce ions in water solution.Difference:
Acids release hydrogen ions (H⁺) whereas, bases release hydroxide ions (OH⁻).Someone help pls.
A s a p
A s a p
A s a p
It’s C. One or more substances with different chemical properties will form.
under what conditions might too much copper go into solution?
An excess of copper may dissolve in a solution during a redox reaction with, for example, a silver nitrate solution where copper wire oxidizes to form copper(II) ions, imbuing the solution with a blue color. Similar conditions can occur in the decomposition of copper from copper ore, chalcocite.
Explanation:Too much copper might go into solution under certain conditions, most commonly in the presence of a chemical reaction where copper is oxidized. For example, when copper wire is placed in a solution containing dissolved silver salt, it undergoes a redox reaction. During this reaction, copper oxidizes to form copper(II) ions, Cu²+ (aq), resulting in a characteristic blue color in the solution due to the dissolved copper ions.
This is the case when the silver nitrate solution reacts with the copper wire. The silver ions are reduced to elemental silver which deposits on the copper wire while copper ions dissolve in the solution. This process spontaneously occurs making the solution more and more blue in color.
An important source of copper is from copper ore, chalcocite, which upon heating decomposes to form copper and sulfur. This is another scenario when copper might dissolve in a solution if the surrounding conditions favor this particular reaction.
Learn more about Copper Dissolution here:https://brainly.com/question/16953296
#SPJ3
what is the oxidation half-reaction for 2Mg+O2
Answer:
Mg --> Mg²⁺ + 2e
Explanation:
Redox reactions consists of both reduction and oxidation reactions.
one species gets oxidised and other species gets reduced, both reactions happen simultaneously giving rise to a redox reaction.
Oxidation reactions could be either loss of electrons or gain of oxygen.
in oxidation the oxidation number of the species will increase
reduction on the other hand is either gain of electrons or gain of hydrogen.
in reduction the oxidation number of the species will reduce
in this reaction the oxidation half reaction is
Mg --> Mg²⁺ + 2e
Mg is losing electrons therefore its being oxidised
the half reaction occuring at the cathode in the balanced reaction shown below is 3MnO4- (aq) + 24H+ + 5Fe (s) ——-> 3Mn2+ + 5Fe3+ + 12H2O
MnO4- (aq) + 8H+ (aq) + 5e− → Mn2+ (aq) + 4H2O (l)
According to the ionic equation, the half reaction which occurs at cathode is MnO₄[tex]^-[/tex] (aq) + 8H [tex]^+[/tex](aq) + 5e− → Mn²[tex]^+[/tex](aq) + 4 H₂O (l).
What is ionic equation?Ionic equation is defined as a chemical equation which represents electrolytes in aqueous solutions and are expressed as dissociated ions. Ions present in aqueous solutions are stabilized by ion dipole interactions with the water molecules which are present.
An ionic equation can be written for any electrolyte which dissociates and reacts with the polar solvent. In a balanced ionic equation , number and type of atoms on each sides of reaction arrow are same. Even the net charge on both sides of the arrow is same.
Strong acids and bases exist as dissociated ions present in the solution and are written in forms of ions in ionic equation.Weak acids and bases do not dissociate completely and hence are written in the form of molecular formula.
Learn more about ionic equation,here:
https://brainly.com/question/15467507
#SPJ2
If the amount of CFCs in the atmosphere decreases, then __.
Plato users: ozone holes could begin to shrink in size
Answer:
Ozone holes could begin to shrink in size.
Explanation:
The use of CFCs today is one of the anthropogenic causes of ozone depletion. CFCs are found in Air conditioners, refrigerators and are excellent coolants.
When CFCs are released into the atmosphere, they react spontaneously with ozone.
Ozone is made up of 3 oxygen atoms and it serves as a protective covering for the very harmful ultraviolet rays from reaching the earth. Ozone cuts off these radiation and it reflects them back into space.
Chloroflurocarbons release Chlroine atoms when they get broken down by ultraviolet rays. The Cl released produces a series of reactions in the presence of ozone.
Chlorine is very reactive as it is an halogen. It requires just an electron to complete its octet.
Chlorine freely reacts with the ozone producing a range of compounds. Most of the ozone becomes oxygen molecules.
This would deplete the ozone greatly. The increasing use of CFCs leaves holes in the ozone layer. The holes allow for harmful UV rays to reach the earth surface. This can lead to various harm on human lives on the earth surface.
This is why CFCs are not permitted in appliances again.
In sexual reproduction, an offspring is produced with genes from both parents. When the offspring has a new genetic variation that it got from neither of its parents, it is called A. an autosome. B. a recessive gene. C. a mutation. D. a phenotype.
Answer:c a mutation
Explanation:
Final answer:
In sexual reproduction, a new genetic variation in offspring that did not come from either parent is called a mutation. Mutations are a key source of genetic diversity and contribute to the evolution of new characteristics within a population. So the correct option is C.
Explanation:
In sexual reproduction, when an offspring exhibits a new genetic variation not found in either parent, this is known as a mutation. Mutations are changes in DNA that serve as the ultimate source of new alleles or new genetic variation within a population. This genetic diversity is essential for the evolution of species, as it allows for adaptations to changing environments and the development of new traits.
Harmless mutations and sexual recombination play a crucial role in the evolution of new characteristics by contributing to genetic diversity. While sexual reproduction can introduce unique combinations of existing genes, it is through mutations that entirely new genetic variations can arise, potentially influencing an organism's phenotype—the observable characteristics of an individual.
This is the process where wind, water or ice may add a layer of sediment to a landform.
Answer:
Deposition
Explanation:
Answer:
Deposition...
Explanation:
Deposition is a process in which the water, ice and wind for layers of sediments when the fluid flow loses it's kinetic energy. After losing energy, the flow of soil in restricted and a layer over layer of soil is formed by deposition called sediments.
Which of the following are not single-displacement reactions?
O A. Fe (s) + 2HCl (aq) → FeCl2(aq) + H2 (9)
B. KOH (aq) + HNO3 (aq) – H20 () + KNO3 (aq)
O C. Na2S (aq) + 2HCl (aq) + 2NaCl (aq) + H2S (g)
O D. Ca (s) + 2H20 (1) ► Ca(OH)2 (aq) + H2 (9)
.
SUBMIT
Answer:
[tex]\boxed{\text{B and C }}[/tex]
Explanation:
In a single-displacement reaction, one element exchanges partners with another element in a compound.
[tex]\textbf{A. } \rm Fe + 2HCl \longrightarrow FeCl_2 + H_2[/tex]
This is a single-displacement reaction, because the element Fe exchanges partners with H in HCl.
[tex]\textbf{B. } \rm KOH + HNO_3 \longrightarrow H_2O + KNO_3[/tex]
This is not a single-displacement reaction, because it is a reaction between two compounds.
This is a double displacement reaction in which the K⁺ and H⁺ cations change partners with the anions.
[tex]\textbf{C. } \rm Na_2S + 2HCl \longrightarrow 2NaCl + H_2S[/tex]
This is not a single-displacement reaction. It is another double displacement reaction, in which the Na⁺ and H⁺ cations change partners with the anions.
[tex]\textbf{D. } \rm Ca + 2HOH \longrightarrow Ca(OH)_2 + H_2[/tex]
This is a single-displacement reaction, because the element Ca exchanges partners with H in H₂O.
[tex]\boxed{\textbf{B and C }}[/tex] are not single-displacement reactions.
what is the percent by mass of a solution that contains 30 grams of potassium nitrite in 0.5 kilograms of water?
Answer:
5.66 %.
Explanation:
mass percent is the ratio of the mass of the solute to the mass of the solution multiplied by 100.
mass % = (mass of solute/mass of solution) x 100.
mass of potassium nitrite = 30.0 g,
mass of the solution = mass of water + mass of potassium nitrite = 500.0 g + 30.0 g = 530.0 g.
∴ mass % = (mass of solute/mass of solution) x 100 = (30.0 g/530.0 g) x 100 = 5.66 %.
how many oxygen molecules are present in 340gm of hydrogen peroxide
Answer:
there are 9.9957 mol O2 in 340 g H2O2
Explanation:
Mw H2O2 = 34.0147 g/molreaction:
H2 + O2 ↔ H2O2⇒ mol H2O2 = 340 g H2O2 * ( mol H2O2 / 34.0147 g H2O2 ) = 9.9957 mol
⇒ mol O2 = 9.9957 mol H2O2 * ( mol O2 / mol H2O2 ) = 9.9957 mol
what is the pressure of 0.33 moles of nitrogen gas, if it's volume is 15.0L at -25.0°C
Answer:
0.448 atm
Explanation:
we can use the ideal gas law equation to find the pressure of nitrogen gas
PV = nRT
where
P - pressure
V - volume
n - number of moles of gas
R - universal gas constant - 0.08206 L.atm/mol.K
T- temperature in kelvin - -25.0 °C + 273 = 248 K
substituting the values in the equation
P x 15.0 L = 0.33 mol x 0.08206 L.atm/mol.K x 248 K
P = 0.448 atm
the pressure of gas is 0.448 atm
The study of chemicals and bonds is called chemistry. According to the law of thermodynamics, the temperature is the move from the high system to the low system.
The correct answer is 0.448 atm.
What is ideal gas law?The ideal gas law, also called the general gas equation, is the equation of the state of a hypothetical ideal gas. It is a good approximation of the behavior of many gases under many conditions, although it has several limitations.The formula used to solve the question is as follows:-
[tex]PV = nRT[/tex]where,
P - pressureV - volumen - number of moles of gasR - universal gas constant - 0.08206 L.atm/mol.KT- temperature in kelvin - -25.0 °C + 273 = 248 KPlacing all the values in the equation.
[tex]P * 15.0 L = 0.33 mol * 0.08206 * 248 K P = 0.448 atm [/tex]
Hence, the pressure of a gas is 0.448 atm
For more information about the ideal gas law, refer to the link:-
https://brainly.com/question/4147359
What volume in mL of a 0.763 M solution of BaI2 would be required if you wanted 0.0131 moles of solute? _____ mL (Picture Attached)
Answer:
The right answer is V = 17.2 mL
Explanation:
Knowing that the the relation between No. of moles and concentration:No. of moles = C * V
where,
C is the concentration in morality and
V is the volume in liter
so you can calculate the volume using:
V = (No. of moles / C) = (0.0131 mol / 0.763 mol/L)
V = 0.0172 L
Then yo need to convert the volume from Liter to milliliterV = 0.0172 L * (1000 mL / 1 L)
V = 17.2 mL
So, the right answer is V = 17.2 mL
A hydrocarbon with this formula C10H22:
is unstable
is unsaturated
is relatively unreactive except for combustion
shares 3 pairs of electrons in the C-C bond
Answer:
is relatively unreactive except for combustion
Explanation:
Answer:
Option 3
Explanation:
Did the odyssey and it's the right answer
which technique often results in the greatest habitat loss
a. silverculture
b. clear- cutting
c. thinning
d. shelterwood harvests
Answer: b. Clear cutting
Explanation:
Clear cutting is the correct option. Clear cutting involves the clearing up of entire vegetation cover of the region or cutting up of trees. This will lead to loss of canopy cover from a region. This will cause loss of biodiversity of a region as the animals, birds and insects will loose their habitat. Such faunal species may translocate to new region, decrease in number or may extinct.
Answer:
It is clear cutting
Explanation:
Clearcutting, clearfelling or clearcut logging is a forestry/logging practice in which most or all trees in an area are uniformly cut down.Clearcutting has been a controversial subject because of its environmental impact. While those who favour this method argue that it allows regenerating trees to have more access to sunlight while it reduces the risk of forest fires in some high-risk areas, opponents point out that in many cases, mass tree removal has caused soil erosion and the destruction of natural habitats for some animals.