Answer:
The independent variable is the calculator
The dependent variable is the speed of solving the problem.
The constant variable is the same set of problems that were assigned to two groups of students.
The dependent variable is the one that is being tested by experimentation. The dependent variable depends on the independent variable.
The independent variable can b changed by the experimenter whereas the constant variable remains unchanged throughout the experiment.
Answer:
Controlled Variable: The same math problems
Dependent Variable: The amount of time taken to answer
Independent Variable: One group using calculators and the other group not using calculators.
Explanation:
The dependent variable is the variable being tested and the independent variable is what is being changed. The controlled is what is staying the same.
If the freezing point depression for a solution is 2. 5°c and kf = 4. 5°c/m, what is the molality of the solution?
Given the freezing-point depression for a solution is 2. 5 °C and the cryoscopic constant is 4.5 °c/m, the molality of the solution is 0.56 m.
What is the freezing-point depression?Freezing-point depression is a drop in the temperature at which a substance freezes, caused when a smaller amount of another, non-volatile substance is added.
The freezing-point depression for a solution is 2. 5 °C. We can calculate the molality of the solution using the following expression.
ΔT = Kf × b
b = ΔT / Kf = 2.5 °C / (4.5 °C/m) = 0.56 m
where,
ΔT is the freezing-point depression. Kf is the cryoscopic constant of the solvent.b is the molality of the solution.Given the freezing-point depression for a solution is 2. 5 °C and the cryoscopic constant is 4.5 °c/m, the molality of the solution is 0.56 m.
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The molality of a solution will be 0.56 m. if the freezing point depression for a solution is 2.5° C.
What is molality?Molality is the measure of the moles of any solute in a solution per unit kg of the solvent.
Given, the freezing-point depression for a solution is 2. 5 °C
The kf is 4.5° c/m
[tex]\rm \Delta T = Kf \times b\\\\b = \dfrac{\Delta T}{kf} \\\\b = \dfrac{2.5^ \circ C}{4.5 \circ C/m} = 0.56 m[/tex]
Where T is freezing point depression
kf is cryoscopic constant of the solvent
b is molality of the solution
Thus, the molality of the solution is 0.56 m.
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A soft drink contains 12.1% sucrose (C12H22O11) by mass. What volume of the soft drink solution in milliliters contains 102.5 g of sucrose? (Assume a density of 1.04 g/mL)
The volume of the soft drink solution in milliliters that contains 102.5 g of sucrose is 11.93mL.
How to calculate volume?The volume of a solution can be calculated by dividing the mass by the density. That is;
Volume = mass/density
According to this question, a soft drink contains 12.1% sucrose (C12H22O11) by mass. This means that the mass of the sucrose is
12.1/100 × 102.5 = 12.40g of sucrose
Volume = 12.40g ÷ 1.04g/mL
Volume = 11.93mL
Therefore, the volume of the soft drink solution in milliliters that contains 102.5 g of sucrose is 11.93mL.
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6)Explain why a 0.010 M solution of hydrochloric acid, HCl has a pH of 2.00 but a 0.010 M solution of
acetic acid, HCH3COO, is 3.37?
0.010 M solution of hydrochloric acid, HCl has a pH of 2.00 but a 0.010 M solution of acetic acid, HCH₃COO, is 3.37 is because HCl dissociates more.
DissociationThis is the separation of ions of an ionic compound when it dissolves.
Hydrogen ion concentration of HClSince 0.010 M solution of hydrochloric acid, HCl has a pH of 2.00 its hydrogen ion concentration is gotten from
pH = -log[H⁺]
So,
[tex][H^{+} ] = 10^{-pH}[/tex]
So, [H⁺] = 10⁻²
Hydrogen ion concentration of HCH₃COOAlso, since 0.010 M solution of acetic acid, HCH₃COO, has a pH of 3.37, its hydrogen ion concentration is gotten from
pH = -log[H⁺]
So,
[tex][H^{+} ] = 10^{-pH}[/tex]
So, [H⁺] = 10⁻³°³⁷ = 0.000427 = 4.27 × 10⁻⁴
Since the hydrogen ion concentration of HCl is 10⁻² and the hydrogen ion concentration of HCH₃COO is 4.27 × 10⁻⁴, we see that HCl dissociates more than HCH₃COO.
So, 0.010 M solution of hydrochloric acid, HCl has a pH of 2.00 but a 0.010 M solution of acetic acid, HCH₃COO, is 3.37 is because HCl dissociates more.
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"Review of the Basics" - WS #1
Directions: Please answer each fill in the blank with the best answer. »
1.
are atoms or groups of atoms that have a positive or negative charge.
2. A
is any atom or group of atoms with a positive charge
Answer: 1. Ions
2. Cation
Explanation:
No explanation; this is basic vocabulary. :)
A footprint of a Tyrannosaurus rex has been found in New Mexico. What type of fossil is this
imprint?
Cast?
Tar seep?
Answer:CAST!!!!!!!!!!!!!!!
Explanation:
Identify the equations that show ionization. check all that apply. upper n a upper c l (s) right arrow upper n a superscript plus (a q) plus upper c l superscript minus (a q). upper h upper c l (g) plus upper h subscript 2 upper o (l) right arrow upper c subscript 3 upper o superscript plus (a q) plus upper c l superscript minus (a q). upper o subscript 2 (g) right arrow upper o subscript 2 (a q). upper c upper o subscript 2 (g) plus 2 upper h subscript 2 upper o (l) right arrow upper h upper c upper o subscript 3 superscript minus (a q) plus upper h subscript 3 upper o superscript plus (a q). upper c a upper c l subscript 2 (s) right arrow upper c a superscript 2 plus (a q) plus 2 upper c l superscript minus (a q).
When an atom gains or donates electrons to form an ion is called ionization. Hydrochloric acid with water and carbon dioxide with water are the ionization reaction.
What are Ionization reactions?In ionization reactions, the chemical species undergo changes to gain or lose electrons to acquire charge.
The reaction between hydrochloric acid and water to yield hydronium ion and chloride ion, and the reaction between carbon dioxide and water to yield hydronium ion and bicarbonate ion is the example of ionization as electrons are donated and gained by the species.
Therefore, the ionization reaction results in the gain or loss of electrons.
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Answer:
B and D just did it
Explanation:
Why do sea turtles rely on instincts more than mammals do?
Answer:
Mammals do not have instincts, so they must learn all their behaviors from their parents in order to survive.
Sea turtles must survive on their own, while mammals spend time with their parents and learn how to survive as they grow.
Sea turtles are less intelligent than mammals and, thus, cannot learn new behaviors from their parents.
Explanation:
Sea turtles rely on instincts more than mammals do, beacuse to get food for their survival.
What are instincts?Insticts are the natural impulse or motivation which are present from the inborn time to perform some functions in order to react in some specific external stimuli.
Mammals do not react impulsively in any external conditions because they have members or friends from their famliy side, who will teach them how to behave or react. But turtles didn't have that special person, so they do work rely on instincts to get food or many other purposes.
Hence, to survive sea turtles rely on instincts more than mammals do.
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what is the valency and symbol of chromium ?
Answer:
two valence states: trivalent chromium (Cr III) and hexavalent chromium (Cr VI)
hope this helps, i can change it if it doesn't.
predict what happens when lead is added to nitric acid
When Lead reacted with nitric acid, lead(II) nitrate, nitrogen oxide and water are produced.
What products are produced when lead reacts with nitric acid?
Lead(II) nitrate, nitrogen oxide and water are the products which are produced by reacting lead and nitric acid with each other. The nitrogen attach with the lead molecule as well as oxygen which produces Lead(II) nitrate and nitrogen oxide.
So we can conclude that when Lead reacted with nitric acid, lead(II) nitrate, nitrogen oxide and water are produced.
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What are 3 ways that radio waves are used in everyday life?
What are 3 ways that infrared waves are used in everyday life?
Thank You!
Explanation:
which of the following is additive inverse of the following
Calculate the kovats retention index for an unknown using the retention times 1. 6 min for ch4, 12. 8 min for octane, 15. 4 min for the unknown, and 19. 6 min for nonane
For an unknown using the retention times 1. 6 min for ch4, 12. 8 min for octane, 15. 4 min for the unknown, and 19. 6 min for nonane, the kovats retention index is mathematically given as
I = 807.857
What is Kovats retention index?Generally, the equation for the Kovats index(i) is mathematically given as
[tex]I= \frac{100[n + (N - n) x (Log tr (unknown) - logtr (n))}{ logtr(N) - logtr(n))]}[/tex]
Therefore
[tex]I= \frac{100[ 1+8*(log(14.7) -log (1.5)}{log (19.8) - log (1.5)) 0]}[/tex]
I = 100[ 1+8*(0.991/1.12)]
I = 807.857
In conclusion, Kovats retention index
I = 807.857
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Kovats retention index is a system that converts the retention time into the independent constants of the system. The Kovats retention index for the unknown is 807.857.
What is the Kovats retention index?The Kovats retention index (I) is the system used in analytical techniques like gas chromatography for the conversion of the retention time. It is given mathematically as:
[tex]\rm I = \rm \dfrac{100[n+(N-n)x(Logtr(unknown)-logtr(n))}{Logtr(N)-Logtr(n)]}[/tex]
Substituting values and solving further,
[tex]\begin{aligned} \rm I &= \rm \dfrac{100[1+8 \times (Log(14.7) - log (1.5))}{(log (19.8) - log (1.5))0}\\\\&= 100 [ 1 + 8 (\dfrac{0.991}{1.12})]\\\\&= 807.857\end{aligned}[/tex]
Therefore, the Kovats retention index for an unknown is 807.857.
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What effect will doubling the initial concentration of crystal violet have on the rate
When the initial concentration of crystal Violet is double, the rate of the reaction will rise up about four times the initial rate.
What is the rate of chemical reaction?The rate of a chemical reaction refer to the rate of change in concentration of the reaction over the change in time. Introduction.
When you double the concentration the rate doubles. The rate is proportional to the square of the concentration of a reactant. When the rate is doubled the concentration rate goes up four times. The rate is not affected by the concentration of a reactant.
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When doubling the initial concentration of crystal violet, the rate will increase four times.
What is the effect of concentration on the rate of a reaction?The rate doubles when the concentration is doubled.
The rate is proportional to the square of a reactant's concentration. When the concentration is doubled, the rate increases fourfold.
The concentration of a reactant has no effect on the rate.
Thus, when doubling the initial concentration of crystal violet, the rate will increase four times.
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Suppose a researcher wanted to extract as much zinc ion as possible from solution a without any copper (ii) impurity. How many milliliters of solution b should the researcher add to solution a?
The extraction of metal usually makes use of the method of precipitation in which a reagent is added which is able to precipitate the required metal in its pure form without impurities.
What is extraction?The process of extraction has to do with the removal of a substance from another. It is usually the way that pure substances are obtained in chemistry. The question is incomplete but I will try to give a general idea.
The extraction of metal usually makes use of the method of precipitation in which a reagent is added which is able to precipitate the required metal in its pure form without impurities. We can not make numerica;l calculatiosn as the values are missing.
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Convert −5 ◦C to Kelvin.
According to the kinetic-molecular theory, what is one way the three states of matter are all similar?
The kinetic molecular theory of matter states that:
1. Matter is made up of particles that are constantly moving.
2. A change in phase may occur when the energy of the particles is changed.
3. All particles have energy, but the energy varies depending on the temperature the sample of matter is in. This in turn determines whether the substance exists in the solid, liquid, or gaseous state.
Are all molecules of ideal gas in motion with different velocities?
Explanation:
Individual gas molecules have different speeds. Collisions between these molecules can change individual molecular speeds, but this does not affect the overall average speed of the system.
What are the examples of physical chemistry?
ANSWER:
Physical chemistry is the branch of chemistry that deals with the physical structure of chemical compounds, the way they react with other matter and the bonds that hold their atoms together. An example of physical chemistry is nitric acid eating through wood.
0.05 moles of HCL are added to 2 L of H2O. What is the molarity of the solution?
Impossible to answer the question with the information provided.
1.60
0.025M
10.4
The molarity of a solution that has 0.05 moles of HCL are added to 2 L of H2O is 0.025M.
How to calculate molarity?The molarity of a solution can be calculated using the following formula:
M = n/V
Where;
M = molarityn = number of molesV = volumeM = 0.05/2
Molarity = 0.025M
Therefore, the molarity of a solution that has 0.05 moles of HCL are added to 2 L of H2O is 0.025M.
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Which are characteristics of photosynthesis? (Select all that apply.) Oxygen is provided to animals from this process. It takes place in the flower of a plant. Plants use this process to make their food. It provides the energy that we obtain from our food.
Answer:
2 , 3 and 4
Explanation:
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How long will hydrogen peroxide make a dog throw up?.
During Taylor's experiment, which piece of data would be qualitative?
mass of the cars
degree of the ramp incline
time in seconds
none are qualitative
From the available options with respect to Taylor's experiment, none of the data is qualitative.
Qualitative dataThese are data that cannot be measured using any instrument or assigned a numerical value.
Qualitative data are observable data based on perception.
This is unlike quantitative data that can be measured using relevant instruments and assigned numeric figures.
Mass can be measured in grams using a weighing balance, angle of inclination can be measured using relevant instruments, and time can be measured using a stopwatch.
Thus, none of the options is qualitative.
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Answer:
None are Qualitative
Explanation: I took the test and got a 100%
what is the barometric trend of the weather data?
Answer:
the change of atmospheric pressure during the last few (generally three) hours before a regular observation.
Explanation:
Even small changes in barometric pressure can greatly impact the weather. The Weather Trend directional arrow icon, included on many AcuRite weather station products, will show one of the following three barometric pressure trend directions, indicating potential future weather conditions.
HELP ITS DUE IN 5 MINS PLSSS Name at least one negative affect that is the result of clearing areas of a rainforest.
Answer:
The loss of trees and other vegetation can cause climate change, desertification, soil erosion, fewer crops, flooding, increased greenhouse gases in the atmosphere, and a host of problems for indigenous people.
Explanation:
What factor would speed up a chemical reaction
Answer:
Adding Catalyst can Speed up a Chemical reaction
Answer: catalyst
Explanation:
a catalyst is a substance that helps speed up chemical reactions.
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which element would be most likely to lose electrons in chemical bond
Which of the following radioactive emissions is the least penetrating?
alpha particles
gamma rays
beta particles
Answer:
alpha particles
Explanation:
alpha particles the least penetrating but potentially most damaging and gamma rays the most penetrating. A beta particle, also called beta ray or beta radiation, is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay.
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Which of the following shows a bronsted-lowry acid reacting? co no2 right arrow. co2 no nh3 h right arrow. nh4 upper c upper o subscript 3 superscript 2 minus. h right arrow. hco3– hcl h2o right arrow. h3o cl–
The reaction which shows the bronsted-lowry acid reacting is HCl + H₂O → H₃O⁺ + Cl⁻.
What is Bronsted - Lowry acid?According to the Bronsted-Lowry theory, the species which donates H⁺ ion to the solution is known as Bronsted-Lowry acid and which accepts H⁺ ion is known as Bronsted-Lowry base.
Among the given reactions, only the reaction which is showing Bronsted-Lowry acid is:
HCl + H₂O → H₃O⁺ + Cl⁻
Here HCl is a Bronsted-Lowry acid as it gives H⁺ ion in the aqueous solution.
Hence, option (3) is correct.
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Can someone please help its due today and im so bad at chemistry
To what temperature must a sample of helium gas be cooled from 139ºC to reduce its volume from 3.1 L to 0.71 L at constant pressure?
Taking into account the Charles's law, to 94.36 K or -178.64 °C must a sample of helium gas be cooled from 139ºC to reduce its volume from 3.1 L to 0.71 L at constant pressure.
Charles's lawThis law states that the volume is directly proportional to the temperature of the gas: for a given sum of gas at constant pressure, as the temperature increases, the volume of the gas increases, and as the temperature decreases, the volume of the gas decreases.
In summary, Charles' law is a law that says that when the amount of gas and pressure are kept constant, the ratio between volume and temperature will always have the same value:
[tex]\frac{V}{T} =k[/tex]
Studying two different states, an initial state 1 and a final state 2, it is satisfied:
[tex]\frac{V1}{T1} =\frac{V2}{T2}[/tex]
Temperature of helium gasIn this case, you know:
V1= 3.1 LT1= 139 C= 412 K (being 0 C= 273 K)V2= 0.71 LT2= ?Replacing in Charles's law:
[tex]\frac{3.1 L}{412 K} =\frac{0.71 L}{T2}[/tex]
Solving:
[tex]\frac{3.1 L}{412 K} T2=0.71 L[/tex]
[tex]T2 =\frac{0.71 L}{\frac{3.1 L}{412 K}}[/tex]
T2= 94.36 K= -178.64 °C
Finally, to 94.36 K or -178.64 °C must a sample of helium gas be cooled from 139ºC to reduce its volume from 3.1 L to 0.71 L at constant pressure.
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Lakshmi has a sample of ammonium nitrate (NH4NO3) that has a mass of 40. 10 g. She knows that the molar mass of NH4NO3 is 80. 0432 g/mol. To the correct number of significant digits, how many moles of NH4NO3 does the sample contain? 0. 50 moles 0. 500979 moles 0. 500980 moles 0. 5010 moles.
Moles are an estimation of the smallest unit of the molecules and the atoms in a sample. The moles of ammonium nitrate in a sample are 0.5010 moles.
What are moles?Moles are calculated by dividing the mass of the substance in gm by that of the molar mass in gram per mole.
Given.
Mass of ammonium nitrate = 40.10 gm
The molar mass of ammonium nitrate = 80. 0432 g/mol
Moles of ammonium nitrate are calculated as:
[tex]\begin{aligned}\rm moles &= \rm \dfrac{mass}{molar\; mass}\\\\&= \dfrac{40.10}{80.0432}\\\\&= 0.5010 \;\rm mol\end{aligned}[/tex]
Therefore, moles of ammonium nitrate present is option d. 0.5010 moles.
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