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You and your lab partner are asked to determine the density of an aluminum bar. The mass is known accurately (to four significant figures). You use a simple metric ruler to measure its dimensions and obtain the results for Method A. Your partner uses a precision micrometer and obtains the results for Method B.
Method A (g/cm3) 2.7 Method B (g/cm3) 2.703 2.701 2.705 5.811
The accepted density of aluminum is 2.702 g/cm 3 .
(a) Calculate the average density for each method.
Should all the experimental results be included in your calculations? If not, justify any omissions.
(b) Calculate the percent error for each method’s average value.
(c) Calculate the standard deviation for each set of data.
(d) Which method’s average value is more precise? Which method is more accurate?
Complete Question
You and your lab partner are asked to determine the density of an aluminum bar. The mass is known accurately (to four significant figures). You use a simple metric ruler to measure its dimensions and obtain the results for Method A. Your partner uses a precision micrometer and obtains the results for Method B.
Method A (g/cm3) 2.2,2.3,2.7,2.4 Method B (g/cm3) 2.703 2.701 2.705 5.811
The accepted density of aluminum is 2.702 g/cm 3 .
(a) Calculate the average density for each method.
Should all the experimental results be included in your calculations? If not, justify any omissions.
(b) Calculate the percent error for each method’s average value.
(c) Calculate the standard deviation for each set of data.
(d) Which method’s average value is more precise? Which method is more accurate?
Answer:
a)[tex]Ma_{avg}= 2.4g/cm^3[/tex]
[tex]Mb_{avg}=2701g/cm^3[/tex]
b)[tex]PE_a=7.5\%[/tex]
[tex]P.E_b=28.8 \%[/tex]
c) [tex]\sigma_A=0.35[/tex]
[tex]\sigma_B=0.0545[/tex]
d)Method A
Explanation:
From the question we are told that:
Method A Density values
2.7
Method B Density values
2.703,2.701,2.705,5.811
Density of aluminium [tex]p_d=2.702 g/cm^3[/tex].
a)
Generally the average density for each method is mathematically given by
Method A
[tex]Ma_{avg}= \frac{2.2+2.3+2.7+2.4}{4}[/tex]
[tex]Ma_{avg}= 2.4g/cm^3[/tex]
Method B
[tex]Mb_{avg}=\frac{2.703+2.701+2.705}{3}[/tex]
[tex]Mb_{avg}=2701g/cm^3[/tex]
b)
Generally the equation for percentage error [tex]PE[/tex] is is mathematically given by
percent error = (measured- real)/real *100
Given real = 2.702 g/ cm3
Method A =
[tex]PE_a=(2.5- 2.702)* \frac{100}{2.702}[/tex]
[tex]PE_a=7.5\%[/tex]
Method B =
[tex]PE_b=( 3.481- 2.702)*\frac{100}{2.702}[/tex]
[tex]P.E_b=28.8 \%[/tex]
c)
Generally the standard deviation [tex]\sigma[/tex] for each method is mathematically given by
Method A
[tex]\sigma=\sqrt{\frac{\sum(x-a)^2}{N} }[/tex]
[tex]\sigma=\sqrt{\frac{0.25+0.16+0+0.09}{4} }[/tex]
[tex]\sigma_A=0.35[/tex]
Method B
[tex]\sigma=\sqrt{\frac{\sum(x-a)^2}{N} }[/tex]
[tex]\sigma=\sqrt{\frac{0.000001+0.00000+0.000009+0.011881}{4} }[/tex]
[tex]\sigma_B=0.0545[/tex]
d)
Therefore with lower percentage error the method who's average value is more precise is
Method A
Answer please correctly
Answer:
the correct answere to that is q
Answer:
D.
Explanation:
Imagine that you have an ideal gas in a 5.80 L container, and that 2950 molecules of this gas collide with a square-centimetre area of the container at any given instant.
If the volume is increased to 46.4 L at constant temperature, how many collisions will occur per square centimetre of this larger container?
Answer:
23,600 collisions.
Explanation:
Hello there!
In this case, according to the Avogadro's law, which help us to understand the molecules-volume relationship as directly proportional:
[tex]\frac{molecules_2}{V_2}=\frac{molecules_1}{V_1}[/tex]
It is possible for us to compute the collisions once the volume is increased as shown below:
[tex]molecules_2=\frac{molecules_1V_2}{V_1}\\\\molecules_2=\frac{2950*46.4L}{5.80L}\\\\molecules_2=23600[/tex]
Which means 23,600 collisions will occur per square centimeter.
Regards!
A rock is made of the same substance while a mineral is made up of different type of
rocks
True
False
Answer:
False i think
pls help What are the benefits and limitations of scientific experiments and investigations?
True or False?
A hydrogen bond is an attraction between molecules containing hydrogen that is not considered a true chemical bond.
Answer:TRUE
Explanation:
A hydrogen bond is the electromagnetic attraction created between a partially positively charged hydrogen atom attached to a highly electronegative atom and another nearby electronegative atom. A hydrogen bond is a type of dipole-dipole interaction; it is not a true chemical bond.
The colder parts of the surface of Pluto have a temperature of –382°F. What is this temperature in Celsius?
How many grams (g) are in 4.00 moles of Carbon (C) ?
Answer:
There are 36 grams in 4.00 moles of Carbon.
Explanation:
In order to convert from moles of a substance into grams of the same substance, we need to use the substance's molar mass.
That means that in this case we use the molar mass of Carbon:
4.00 mol * 12 g/mol = 36 gThus, there are 36 grams in 4.00 moles of Carbon.
What is the pH of a neutral solution at 25ºC?
a. 14
b. 0
c. 1
d. 7
Answer:
d.7 is the correct answer
Water is amphoteric. If it reacts with a compound that is a stronger acid than itself, water acts as a
Answer:
Water acts as a base in the presence of a strong acid
Explanation:
Water,being an amphoteric compound, can act both as an acid and as a base.
In the presence of an acid , water acts as a base but in the presence of a base, water acts as an acid.
C12H26+Oxygen=12CO2+water
calculate the mass of one mole of the liquid alkane C12H26.
Answer:
170.38g is the mass of 1 mole of C₁₂H₂₆
Explanation:
To solve this question we must find the molar mass of the alkane C₁₂H₂₆. The molar mass is defined as the mass of one mole of a substance.
In 1 mole of C₁₂H₂₆ we have 12 moles of Carbon and 26 moles of Hydrogen. With the periodic table of elements we can know the molar mass of 1 mole of Carbon and 1 mole of hydrogen, and, thus, the molar mass of the alkane (Molar mass C = 12.01g/mol, H = 1.01g/mol)
Molar mass C₁₂H₂₆:
12C = 12*12.01g/mol = 144.12g/mol
26H = 26*1.01g/mol = 26.26g/mol
144.12g/mol + 26.26g/mol =
170.38g is the mass of 1 mole of C₁₂H₂₆Which is the correct statement regarding the relative Rf values of the starting methyl benzoate vs the product, methyl m-nitrobenzoate on a silica gel TLC plate. The product has a higher Rf value on a silica gel TLC plate because it is less polar than the starting methyl benzoate. The product has a lower Rf value on a silica gel TLC plate because it is less polar than the starting methyl benzoate. The product has a higher Rf value on a silica gel TLC plate because it is more polar than the starting methyl benzoate. The product has a lower Rf value on a silica gel TLC plate because it is more polar than the starting methyl benzoate. 1.5 points QUESTION 2 Methyl benzoate is more reactive than benzene in Electrophilic Aromatic Substition [EAS] reactions. True False 1 points QUESTION 3 Methyl m-nitrobenzoate is less reactive than methyl benzoate in Electrophilic Aromatic Substition [EAS] reactions. True False
Answer:
1. The product has a higher Rf value on a silica gel TLC plate because it is more polar than the starting methyl benzoate.
2. False
3. True
Explanation:
In chromatography, there is a stationary phase and a mobile phase. The ratio of the distance moved by a component and the distance moved by the solvent gives the retention factor (Rf).
Since silica gel is a polar solvent, it will retain the more polar product methyl m-nitrobenzoate compared to the methyl benzoate starting material.
In comparing the electrophillic aromatic substitution of m-nitrobenzoate and methyl benzoate, we must remember that the presence of electron withdrawing groups (such as -NO2 and -CHO) on the aromatic compound deactivates the compound towards electrophillic aromatic substitution hence, methyl m-nitrobenzoate is less reactive than methyl benzoate in Electrophilic Aromatic Substition and Methyl benzoate is less reactive than benzene in Electrophilic Aromatic Substition
The final result has a higher Rf value because the TLC plate has more polarity than the other compound.
The answer to the following question is as follows:-
False True
In chromatography, it is a process that is used to separate the different components on the basis of their votality. The ratio of the distance moved by a component and the distance moved by the solvent gives the retention factor (Rf).
In comparing the electrophilic aromatic substitution of m-nitrobenzoate and methyl benzoate, we must remember that the presence of electron-withdrawing groups on the aromatic compound deactivates.
The compound towards electrophilic aromatic substitution hence, methyl m-nitrobenzoate is less reactive than methyl benzoate in Electrophilic Aromatic Substitution and Methyl benzoate is less reactive than benzene in Electrophilic Aromatic Substitution.
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Plzzzzz help me to solve this question.
Answer:
Explanation:
A1. Chemical indicator, any substance that gives a visible sign, usually by a colour change, of the presence or absence of a threshold concentration of a chemical species, such as an acid or an alkali in a solution. An example is the substance called methyl yellow, which imparts a yellow colour to an alkaline solution.
A2. The reaction of an acid with a base is called a neutralization reaction. The products of this reaction are a salt and water. ... For example, the reaction of hydrochloric acid, HCl, with sodium hydroxide, NaOH, solutions produces a solution of sodium chloride, NaCl, and some additional water molecules
A3. Methyl orange has the property to color alkaline and neutral water yellow. If the water becomes acidic, it turns red immediately.
3. You will need to make ~0.1 M solutions of one (or more) of the following salts. For each compound, determine (or look up) its molecular weight, and determine the mass necessary to make 100.0 mL of 0.100 M solution. Pay attention to significant figures! Sodium acetate anhydrous Sodium acetate trihydrate Iron(III) chloride hexahydrate g
Answer: The mass of sodium acetate anhydrous required is 0.820 g
The mass of sodium acetate trihydrate required is 1.36 g
The mass of Iron (III) chloride required is 2.70 g
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]
where,
n = moles of solute
= volume of solution in ml
1. moles of =
Now put all the given values in the formula of molarity, we get
[tex]0.100=\frac{x\times 1000}{82.03\times 100.0}[/tex]
[tex]x=0.820g[/tex]
Therefore, the mass of sodium acetate anhydrous required is 0.820 g
2. moles of [tex]CH_3COONa.3H_2O[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{xg}{136.08g/mol}[/tex]
Now put all the given values in the formula of molarity, we get
[tex]0.100=\frac{x\times 1000}{136.08\times 100.0}[/tex]
[tex]x=1.36[/tex]
Therefore, the mass of sodium acetate trihydrate required is 1.36 g
3. moles of [tex]FeCl_3.6H_2O[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{xg}{g/mol}[/tex]
Now put all the given values in the formula of molarity, we get
[tex]0.100=\frac{x\times 1000}{270.33\times 100.0}[/tex]
[tex]x=2.70g[/tex]
Therefore, the mass of Iron (III) chloride required is 2.70 g
How does the ozone layer work?
Answer:
The atmosphere acts like a multi-layer shield that protects Earth from dangerous solar radiation. ... The stratospheric ozone layer absorbs ultraviolet (UV) radiation, preventing dangerous UV rays from hitting Earth's surface and harming living organisms. (Just look it up)
Explanation:
I hope this helps!
Electricity is possible because atoms release and absorb which sub-atomic particle?
Answer:
Electrons
Electric charge is carried by subatomic particles such as electrons and protons, which can be created and destroyed. For example, when particles are destroyed, equal numbers of positive and negative charges are destroyed, keeping the net amount of charge unchanged.
Predict the products for the reaction shown in the picture.
Fe(s) + CuCrO4(aq) —>
Answer:
After checking many websites as well
I haven't seen any answer for this reaction
While I found answers or other reactions
Therefore I think this reaction cannot occur
Please mark my answer as brainliest if you feel I helped you in any way :)
Which of the following elements will form positive ions? Check all
that apply.
Na
z
Cu
Br
Answer:
cu and Na
Explanation:
When an atom losses electrons this results in a positive charge. A positively charged ion is called a cation.
Sodium and copper will form positive ions. Sodium is a monovalent cation while copper is a divalent cation.
What are positive ions?The ions which contain a positive charge it is called positive ions. The atomic number of sodium is 11. It contains (2, 8, 1) electrons. When it loses it's one electron it will be a positive ion.
Copper has valence electrons. When it loses its two valence electrons it will be a copper ion. There are two types of ions such as positive ions and negative ions.
Small molecules that have acquired a positive charge are known as positive ions. Positive ions are the predominant type of air pollution, including hazardous substances, pollen, mold, pet dander, and other dangerous chemicals.
Therefore, Sodium and copper will form positive ions. Sodium is a monovalent cation while copper is a divalent cation.
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The following containers have the same number of molecules and temperature. Which container has the most collisions?
Answer:
Container 1 I think.
The containers have the same number of molecules and temperature. The container 1.
What is collision?Collision is the encounter between two particles or object. There are three type of collision: perfectly elastic collision, inelastic collision, perfectly inelastic collision.
Container 1 is smallest, so there will be less distance between the molecules, so they will collide most.
Thus, the containers have the same number of molecules and temperature. The container 1.
Learn more about collision
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Eaterfication experiment
Answer:
Do you mean Esterification experiment?
Explanation:
Redox reactions refer to a pair of reactions in which a particular oxidation is coupled to a corresponding reduction.
a. True
b. False
Answer:
A. True
Explanation:
How many moles are there in 87.2 g of zinc fluoride?
Answer:
what I got was 0.8435160945347224 moles
Select the correct structure that
corresponds to the name.
3-bromo-6-methyl-4-octene
CHE
A
Br
B.
CH3CH2CHBrCH = CHCH(CH3)CH2CH3
C. both
Someone please help
Answer:
b
Explanation:
one clue is the double bond at 4 carbon c=c
The correct structure that corresponds to the name.
3-bromo-6-methyl-4-octene is [tex]$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHBrCH}=\mathrm{CHCH}\left(\mathrm{CH}_{3}\right) \mathrm{CH}_{2} \mathrm{CH}_{3}$[/tex] .
What is 3-bromo-6-methyl-4-octene?The molecule in which bromine is attached with C-3 carbon and double present at C-4 carbon containing total number of 8 carbon atom can be considered as 3-bromo-6-methyl-4-octene.
What is structure?
A chemist specifies the molecular geometry and, where possible and required, the electronic structure of such given molecule as well as other solid during a chemical structure determination.
It can be seen that in molecule [tex]$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHBrCH}=\mathrm{CHCH}\left(\mathrm{CH}_{3}\right) \mathrm{CH}_{2} \mathrm{CH}_{3}$[/tex] bromine is attached with C-3 carbona and double bond exist at C-4 carbon. the total number of carbon atom is 8.
therefore, the structure of the compound will be [tex]$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHBrCH}=\mathrm{CHCH}\left(\mathrm{CH}_{3}\right) \mathrm{CH}_{2} \mathrm{CH}_{3}$[/tex].
To know more about structure of the 3-bromo-6-methyl-4-octene click here.
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Sulfuric acid (H₂SO₄), is formed when sulfur dioxide (SO₂) reacts with oxygen and water. Using the balanced chemical reaction above, how many moles of H₂SO₄ are produced from 8.5 moles of SO₂?
Answer:
8.5 mol H₂SO₄
Explanation:
It seems the balanced reaction the problem is referring to is absent, however the description matches the following balanced reaction:
2SO₂ + O₂ + 2H₂O → 2H₂SO₄Now we can convert 8.5 moles of SO₂ into moles of H₂SO₄, using the stoichiometric coefficients of the balanced reaction:
8.5 mol SO₂ * [tex]\frac{2molH_2SO_4}{2molSO_2}[/tex] = 8.5 mol H₂SO₄The Haber Process synthesizes ammonia at elevated temperatures and pressures. Suppose you combine 1580 L of nitrogen gas and 4595 L of hydrogen gas at STP, heat the mixture to run the reaction, then isolate the ammonia from the reaction mixture. What volume of NH₃ in liters, measured at STP, would be produced? Assume the reaction goes to completion.
N₂ (g) + 3 H₂ (g) → 2 NH₃ (g)
Answer:
The volume of reactant measured at STP left over is 409.9 L
Explanation:
What is neutralisation reaction? Give an example with reaction involved. State two uses of neutralisation reaction in everyday life.
Answer:
neutralization reaction is when an acid and a base react to form water and salt and involves the combination of hydrogen ions and hydroxyl ions to generate water. The neutralization of a strong acid and strong base has a pH equal to 7.
Two students come up with an idea they think will save time: We just used the fast titrations. You can stop the video when the solution turns pink. We know that when the solution turns pink, the titration is complete, so we just read the volume from the burette as soon as it turns pink. This is faster than going through all the shorter videos and works just as well. Is this method just as accurate as using the slow titrations
Answer:
Yes.
Explanation:
Yes, this method is accurate just as the slow titration because in both type of titrations we want to measure the point at which the indicator change the colour of the solution. Both fast and slow titrations are the same in their function i.e. both tell us the point or the amount at which the indicator change the colour of the solution so we can conclude from this discussion that fast titration gives the same result just as the slow titration.
If the pH of a solution is 1.5 , calculate [H^ + ] .
Help plz??
Answer: Thus hydrogen ion concentration is 0.031622777
Explanation:
pH or pOH is the measure of acidity or alkalinity of a solution.
pH is calculated by taking negative logarithm of hydrogen ion concentration.
[tex]pH=-\log [H^+][/tex]
Putting in the values:
[tex]1.5=-\log[H^+][/tex]
[tex][H^+]=10^{-1.5}=0.031622777[/tex]
Thus hydrogen ion concentration is 0.031622777
Plz help me I am timed!!
Which of the following correctly shows a synthesis reaction involving potassium?
A. Br2 + 2KI → I2 + 2KBr
B. 4K + O2 → 2K2O
C. 2KClO3 → 2KCl + 3O22KClO3 → 2KCl + 3O2
D. 2K2O → 4K + O22K2O → 4K + O2
Answer:
B. 4 K + O₂ → 2 K₂O
Explanation:
Which of the following correctly shows a synthesis reaction involving potassium?
A. Br₂ + 2 KI → I₂ + 2 KBr
No, this is a single displacement reaction, in which Br displaces I from its salt.
B. 4 K + O₂ → 2 K₂O
Yes, this is a synthesis reaction, in which 2 elements combine to form a compound.
C. 2 KClO₃ → 2 KCl + 3 O₂
No, this is a decomposition reaction, in which a big substance decomposes into smaller ones.
D. 2 K₂O → 4K + O₂
No, this is a decomposition reaction, in which a big substance decomposes into smaller ones.