develop a theory. develop a hypothesis. support a hypothesis
When 125 mL of 0.150 M Pb(NO3)2 is mixed with 145 mL of 0.200 M KBr, 4.92 g of PbBr2 is collected. Calculate the percent yield.
Answer:
Y = 92.5 %
Explanation:
Hello there!
In this case, since the reaction between lead (II) nitrate and potassium bromide is:
[tex]Pb(NO_3)_2+2KBr\rightarrow PbBr_2+2KNO_3[/tex]
Exhibits a 1:2 mole ratio of the former to the later, we can calculate the moles of lead (II) bromide product to figure out the limiting reactant:
[tex]0.125L*0.150\frac{molPb(NO_3)_2}{L} *\frac{1molPbBr_2}{1molPb(NO_3)_2} =0.01875molPbBr_2\\\\0.145L*0.200\frac{molKBr}{L} *\frac{1molPbBr_2}{2molKBr} =0.0145molPbBr_2[/tex]
Thus, the limiting reactant is the KBr as it yields the fewest moles of PbBr2 product. Afterwards, we calculate the mass of product by using its molar mass:
[tex]0.0145molPbBr_2*\frac{367.01gPbBr_2}{1molPbBr_2} =5.32gPbBr_2[/tex]
And the resulting percent yield:
[tex]Y=\frac{4.92g}{5.32g} *100\%\\\\Y=92.5\%[/tex]
Regards!
Order the following chemicals from lowest to highest melting point.
Tungsten
Copper (II) chloride
• Caffeine
• Lead
• Sodium chloride
• Silver
Answer
• Silver
• copper
Imagine a unit of charge called the zorg. A chemist performsthe oil drop experiment and measures the charge of each drop inzorgs. Based on the results below, what is the charge of theelectron in zorgs (z)? How many electrons are in eachdrop?
Drop # Charge
A -4.8 x 10^-9 z
B -9.6 x 10^-9 z
C -6.4 x 10^-9 z
D -12.8 x 10^9z
Answer:
-1.6 × 10⁻⁹ z
Explanation:
To attempt this type of question, we need to first divide each charge present in the question with the smallest one.
i.e.
[tex]A = \dfrac{-4.8 \times 10^{-9}}{-4.8 \times 10^{-9}}= 1[/tex]
[tex]B = \dfrac{-9.6 \times 10^{-9}}{-4.8 \times 10^{-9}}= 2[/tex]
[tex]C= \dfrac{-6.4 \times 10^{-9}}{-4.8 \times 10^{-9}}= 1.33[/tex]
[tex]D= \dfrac{-12.8 \times 10^{-9}}{-4.8 \times 10^{-9}}= 2.67 \simeq 3[/tex]
The next thing to do is to multiply each obtained value with the highest integer
A = 1 × 3 = 3
B = 2 × 3 = 6
C = 1.33 × 3 = 3.99
D = 3 × 3 = 9
Finally, we divide each charge by the result from above.
[tex]A = \dfrac{-4.8 \times 10^{-9}}{3}= -1.6 \times 10^{-9}[/tex]
[tex]B = \dfrac{-9.6 \times 10^{-9}}{6}= -1.6\times 10^{-9}[/tex]
[tex]C= \dfrac{-6.4 \times 10^{-9}}{3.99}= -1.6\times 10^{-9}[/tex]
Thus, we can therefore easily conclude that the charge in zorgs (z) is:
-1.6 × 10⁻⁹ z
Which hydrocarbon is saturated?
A)
heptyne
B)
butane
C)
propene
D)
ethyne
How to change τhe color of silver mercury to red???
Answer: This is the hue of mercury if you're looking for it. Mercury reacts with sulphur to generate a crimson hue. In the past, they always used a thermometer.
Explanation: However, due of its toxicity, individuals have switched to using alcohol in glass thermometers, which work similarly to mercury thermometers.
hope this helped best of luck mate! :) if this helped make sure to mark me Brainliest!
Tryptophan, an essential amino acid, is important in the synthesis of the neurotransmitter serotonin in the body.
a. True
b. False
Answer:
B porque si :) y eso Jsksjs
Answer:A
Because it's an amino acid and all amino acids are key to any part of your body.
an experiment is carried out to determine the formula of an oxide of mercury. the oxide is a red solid. it decomposed into its elements when heated at room temperature and pressure (r.t.p.). // mass of oxide of mercury: 2.16g // volume of oxygen collected at r.t.p.: 120cm³ // what is the mass of mercury produced?
Answer:
Mass of mercury produced = 2.00 g
Explanation:
At room temperature and pressure, the temperature T = 25° C or 298.15 K while the pressure = 1 atmosphere or 760 mmHg.
Mass of oxide of mercury decomposed at room temperature and pressure = 2.16 g
Volume of oxygen produced = 120 cm³ or 0.12 dm³
One mole of any gas has a volume of 24 dm³ at room temperature and pressure.
Therefore, number of moles of oxygen produced = 0.12 dm³ / 24 dm³/mol = 0.005 moles
Mass of oxygen produced = number of moles × molar mass
Molar mass of oxygen = 32 g/mol
Mass of oxygen produced = 0.005 moles × 32 g/mol = 0.16 g
Thus, mass of mercury produced = mass of mercury oxide decomposed - mass of oxygen produced
Mass of mercury produced = 2.16 g - 0.16 g
Mass of mercury produced = 2.00 g
Which subatomic particles each have a mass of approximately 1 u?
A)
proton and electron
B)
proton and neutron
C)
neutron and electron
D)
neutron and positron
Answer:
be is the answer to your question
Dichlorine monoxide, Cl2O is sometimes used as a powerful chlorinating agent in research. It can be produced by passing chlorine gas over heated mercury (II) oxide according to the following equation: HgO + Cl2 ????HgCl2 + Cl2O What is the percent yield, if the quantity of the reactants is sufficient to produce 0.86g of Cl2O but only 0.71 g is obtained?
Answer:
% yield = 82.5%
Explanation:
HgO + 2Cl₂ → HgCl₂ + Cl₂O
Our reactants are:
HgO and Cl₂Our products are:
HgCl₂ + Cl₂OWe do not have information about moles of reactants, but we do know the theoretical yield and the grams of product, in this case Cl₂O, we have produced.
Percent yield = (Yield produced / Theoretical yield) . 100
Theoretical yield is the mass of product which is produced by sufficent reactant. We replace data:
% yield = (0.71 g/0.86g) . 100 = 82.5%
The percent % yield = 82.5%
The balanced chemical equation will be:
HgO + 2Cl₂ → HgCl₂ + Cl₂O
The reactants participating in this reaction are: HgO and Cl₂
The products so formed are: HgCl₂ + Cl₂O
[tex]\text{ Percent yield} = \frac{\text{Yield produced}}{\text{Theoretical yield}} *100[/tex]
The theoretical yield is the maximum possible mass of a product that can be made in a chemical reaction.
[tex]\text{Percent yield}= \frac{0.71 g}{0.86g} * 100 \\\\\text{Percent yield}= 82.5\%[/tex]
Thus, the percent yield is 82.5%.
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CuCl2(aq) + KOH(aq)--------------->Cu(OH)2(aq) + KCl(aq)
Answer:
CuCl2 (aq) + 2 KOH (aq) → Cu(OH)2 (s) + 2 KCl (aq)
Explanation:
I did it.
Answer:
CuCl2 + 2KOH------------------>Cu(OH)2 + 2KCl
Explanation:
this is the right solution of equation
Explain your understanding of functional group in organic chemistry
Answer:
A functional group in organic chemistry is an atom or group of atoms that is responsible for the specific properties of an organic compound. Some examples of functional groups include alcohols, alkyl halides, ethers, aldehydes, ketones, amines, carboxylic acids, and esters.
Functional groups also play an important part in organic compound nomenclature; combining the names of the functional groups with the names of the parent organic compounds provides a way to distinguish compounds.
The atoms of a functional group are linked together and to the rest of the compound by covalent bonds. The first carbon atom that attaches to the functional group is referred to as the alpha carbon; the second, the beta carbon; the third, the gamma carbon, etc. Similarly, a functional group can be referred to as primary, secondary, or tertiary, depending on if it is attached to one, two, or three carbon atoms.
How does activation energy affect a chemical reaction?
Answer:
It determines how difficult it is to start the reaction.
Explanation:
I need to summarize each type of radioactive decay.
Answer:
1. alpha - decreased mass by 4 - decrease atomic number by 2
2. beta electron - no change - increase by 1
3 - beta positron - no change - decrease by 1
4. gamma - no change - no change
5. electron capture - no change - decrease by 1
Explanation:
There are five main types of radioactive decay, a process where the nucleus loses energy by emitting radiation, these radiation or type of radioactive decay are alpha particles, beta particles, positron or beta positron, gamma particles and electron capture.
The effect of these particles causes a change in the number of subatomic which leads to different atomic mass and atomic numbers after the decay -
1. alpha - decreased mass by 4 - decrease the atomic number by 2
2. beta electron - no change - increase by 1
3 - beta positron - no change - decrease by 1
4. gamma - no change - no change
5. electron capture - no change - decrease by 1
The molecular mass of a compound is determined to be 180.0 and a composition of 60.0% C and 4.48% H and the remainder is Oxygen. What is the molecular formula of the compound.
Answer:
18%.0
Explanation:
hipe it helps
pa brainlist
Calculate the mass in grams of 24.5 mL of diethyl ether, an anesthetic that has a density of 0.713 g/mL. Round your answer to the tenth's place.
Answer:
17.48
Explanation:
mass=density×volume
= 0.713g/ml × 24.5 ml
= 17.4685
≈ 17.47
electron affinity of lithium is -60 whereas of cesium is -45.this trend is due to... plz give me accurate answer
A sample of 0.2140 g of an unkown substance monoprotic acid was dissolved in 25.0 mL of water and titrated with 0.950 M NaOH. The acid required 27.4 mL of base to reach the equivalence point. After 15.0 mL of base had been added in the titration, the pH was found to be 6.50. What is the Ka for the unknown acid?
Solution :
The equation is :
[tex]$HA (aq) + NaOH(aq) \rightleftharpoons NaA(aq) + H_2O(l)$[/tex]
The number of the moles of HA os 0.00285, and the volume is 25 mL.
15 mL of the 0.0950 M NaOH is added.
The total volume of a solution is V = 25 mL + 15 mL = 40 mL
The pH of the solution is 6.50
Calculating the [tex]K_a[/tex] of HA
[tex]$HA(aq) \rightleftharpoons A^-(aq)+H^+$[/tex]
[tex]K_a=\frac{[A^-].[H^+]}{[HA]}[/tex]
Let s calculate the concentration of HA and NaOH
[tex]$[HA] = \frac{^nH_A}{V}$[/tex]
[tex]$=\frac{0.00285 \ mol}{0.04 \ L}$[/tex]
= 0.07125 M
[tex]$[NaOH]= \frac{0.015L \times 0.0950 M}{V}$[/tex]
[tex]$=\frac{0.001425 mol}{0.04L}$[/tex]
= 0.0356 M
[tex]$HA(aq) \ \ + \ \ NaOH(aq) \ \ \rightleftharpoons NaA(aq) \\ + \ \ H_2O(aq)$[/tex]
Initial conc. (M) 0.07125 M 0.0356 M 0 M
Change in conc. (M) -0.0356 M -0.0356 M + 0.0356 M
Equilibrium conc. (M) 0.03565 M 0 M 0.0356 M
Therefore, the concentration of HA and the NaA at the equilibrium are [HA] = 0.03565 M and [NaA]= 0.0356 M
0.0356 M of NaA dissociates completely into 0.0356 M [tex]Na^+[/tex] and 0.0356 M [tex]A^-[/tex]
Now for [tex][H^+][/tex]
[tex]$[H^+] = 10^{-pH}$[/tex]
[tex]$=10^{-6.5}$[/tex]
[tex]$=3.16 \times 10^{-7}$[/tex]
Calculating the value of [tex]K_a[/tex],
[tex]K_a=\frac{[A^-].[H^+]}{[HA]}[/tex]
[tex]$=\frac{0.0356 \times 3.16 \times 10^{-7}}{0.03565}$[/tex]
[tex]$=3.16\times 10^{-7}$[/tex]
Therefore the the value of [tex]K_a[/tex] for the unknown acid is [tex]$3.16\times 10^{-7}$[/tex].
Use the graph to calculate the instantaneous rate of formation of HBr at 50 s
Express your answer using one significant figure.
Answer: The instantaneous rate of formation of HBr at 50 s is [tex]1.4\times 10^{-2}M/s[/tex]
Explanation:
From the graph,
Initial rate of the [tex]Br_2[/tex] = 1.0 M
Time when the concentration of [tex]Br_2[/tex] is 0.5 M (half the concentration ) = 60 sec
For first order reaction:
Calculating rate constant for first order reaction using half life:
[tex]t_{1/2}=\frac{0.693}{k}[/tex] .....(1)
[tex]t_{1/2}[/tex] = half life period = 60 s
k = rate constant = ?
Putting values in equation 1:
[tex]k=\frac{0.693}{60s}\\\\k=0.01155s^{-1}[/tex]
For the given chemical reaction:
[tex]H_2(g)+Br_2(g)\rightarrow 2HBr(g)[/tex]
Rate of the reaction = [tex]-\frac{\Delta [Br_2]}{\Delta t}=\frac{1}{2}\frac{\Delta [HBr]}{\Delta t}[/tex]
Negative sign represents the disappearance of the reactants
From the above expression:
[tex]k[Br_2]=-\frac{\Delta [Br_2]}{\Delta t}=\frac{1}{2}\frac{\Delta [HBr]}{\Delta t}[/tex]
At 50 seconds, [tex][Br_2]=0.6 M[/tex]
Plugging values in above expression, we get:
[tex]\frac{1}{2}\frac{\Delta [HBr]}{\Delta t}=0.01155\times 0.6\\\\\frac{\Delta [HBr]}{\Delta t}=2\times 0.01155\times 0.6=0.01386=1.4\times 10^{-2}M/s[/tex]
Hence, the instantaneous rate of formation of HBr at 50 s is [tex]1.4\times 10^{-2}M/s[/tex]
Volumes of 0.18M copper (II) sulfate, and water.
6.5ml 0.18M CuSO4
4.0ml H20
This is my chemistry finals, I need help immediately!
Answer:
See explanation
Explanation:
Number of moles of Copper sulphate = 0.18 M × 6.5/1000= 1.17 × 10^-3 moles of CuSO4
From;
number of moles = mass/molar mass
Molar mass of copper II sulphate = 160g/mol
1.17 × 10^-3 moles = mass/160g/mol
Mass = 1.17 × 10^-3 moles ×160
Mass = 0.187 g
If 1 mole contains 6.02 × 10^23 molecules
1.17 × 10^-3 moles contains 1.17 × 10^-3 moles × 6.02 × 10^23/1 = 7 × 10^20 molecules
From;
C1 V1=C2 V2
0.18 × 6.5 =C2 × 10.5
C2 = 0.18 × 6.5/10.5
C2=0.11 M
CuSO4(aq) + 2NaOH(aq) ----> Cu(OH)2(s) + Na2SO4(aq)
1 mole of CuSO4 yields 1 mole of Cu(OH)2
1.17 × 10^-3 moles of CuSO4 yields 1.17 × 10^-3 moles of Cu(OH)2
Mass of Cu(OH)2 = 1.17 × 10^-3 moles × 98g/mol= 0.11g of Cu(OH)2
Read the given equation:
NH + HCI - NH4ACI
Which of the following is true about the equation?
NH3 is the acid and NH4Cl is the salt.
NH3 is the base and NH4Cl is the salt.
HCI is the acid and NH3 is the salt.
HCl is the base and NH3 is the salt.
Answer:
NH3 is the base and NH4Cl is the salt.
Explanation:
Hello there!
In this case, according to the given information, it is possible for us to rewrite the chemical equation and thus obtain:
[tex]NH_3+HCl\rightarrow NH_4Cl[/tex]
Whereas it is possible to notice that ammonia, NH3, received the hydrogen ions from HCl to form NH4 ions and Cl ions; in such a way, we infer that NH3 is the base and NH4Cl is the salt.
Regards!
Answer:
NH3 is the base and NH4Cl is the salt
Explanation:
Assuming no other changes, what is the effect of doubling only the concentration of the alkyl halide in the above SN2 reaction?
A) no change
B) triples the rate
C) rate is halved
D) doubles the rate
E) quadruples the rate
Answer:
D) doubles the rate
Explanation:
The given reaction is :
[tex]$CH_3Br + OH^- \rightarrow CH_3OH+Br^-$[/tex]
For the [tex]SN^2[/tex] reaction, the rate of reaction depends upon the concentration of both the [tex]$\text{alkyl halide}$[/tex] as well as the [tex]\text{nucleophile.}[/tex]
That is the rate = [tex]$k[CH_3Br][OH^-]$[/tex]
Now if the [tex]$[CH_3Br]$[/tex] becomes [tex]$2[CH_3Br]$[/tex], then the rate becomes double.
So the rate' is :
= [tex]$2k[CH_3Br][OH^-]$[/tex]
= 2 x rate
Therefore, the answer is (D) doubles the rate.
What is the Kc expression for this reaction?
2 NO(g) + O2(g) ⇌ 2 NO2(g)
a)Kc = [NO2]2 / [NO]2 [O2]
b)Kc = [NO]2 [O2] / [NO2]2
c)Kc = [NO]2 [O2] [NO2]2
d)Kc = [NO2]2 / [NO]2 + [O2]
Answer:
D
Explanation:
because product are at the top and reactant are at the bottom also it to the power of the moles in front e.g 2NO it will be to the power of 2 in this case.
hope it make sense :)
Someone please help me with this
Answer:
I think A should be the answer because oxygen is the chemical change of carbon.
briefly describe the action of hardwater with soap
Answer:
The correct answer is - hard water reacts to form the calcium or magnesium salt of the organic acid of the soap.
Explanation:
Soaps are made up of fatty acids or oils by treating with strong alkali and are salts of sodium and potassium. Hard water, on the other hand, has a high concentration of minerals in comparison to soft water. When hard water and soap are mixed together the salts of the minerals like Ca2+ and Mg2+ ions present in hard water react with fatty acids of the soap.
The sodium salts are changed to the salts of calcium and magnesium which are precipitated to an insoluble substance. The insoluble salts of the calcium or magnesium dirt stick on the clothes thus cleaning ability of soap is reduced.
Why do powders react faster than lumps?
1)Particles of a powder have a lower activation energy
2)Collisions between reactant particles are more frequent
3)Particles of a powder move faster
The more finely divided the solid is, the faster the reaction happens. A powdered solid will normally produce faster reaction than if the same mass is present as a single lump. The powdered solid has a greater surface than the single lump
Explanation:
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Helppp
What do you need to know in order to find the mass of 3.00 moles of carbon?
Answer:
36g
Explanation:
you need to know the equation mass=moles*mr (in this case mr of carbon which is 12)
so 3*12=36g
hope this helps :)
when ice melts,its volume
Answer:
There isn't enough information to answer you're question.
Explanation:
Have a great day!!!
rank in order the strongest to the weakest acid cbr3cooh, ch3cooh and ccl3cooh
Answer: Rank in order the strongest to the weakest acid is [tex]CCl_{3}COOH[/tex] > [tex]CBr_{3}COOH[/tex] > [tex]CH_{3}COOH[/tex].
Explanation:
More readily a substance is able to donate a hydrogen ion more will be its acidic strength. Hence, stronger will be the acid.
More is the electronegativity of atoms attached to the acid more easily it will donate a proton. Hence, more will be its acidic strength.
Chlorine is more electronegative in nature as compared to bromine. So,
[tex]CCl_{3}COOH[/tex] is more acidic than [tex]CBr_{3}COOH[/tex].
Since there is no electronegative group attached to [tex]CH_{3}COOH[/tex] so it is least acidic than [tex]CCl_{3}COOH[/tex] and [tex]CBr_{3}COOH[/tex].
Thus, we can conclude that rank in order the strongest to the weakest acid is [tex]CCl_{3}COOH[/tex] > [tex]CBr_{3}COOH[/tex] > [tex]CH_{3}COOH[/tex].
What should the coefficient for the diatomic oxygen (O2) be when this equation is correctly balanced
3
And then for Fe it should be 4 and for the products it should be 2!!
Rank the compounds below in order of decreasing base strength.
a. HPO4^2-
b. NH3
c. NO2
d. SO4^2-
Answer:
c. NO2
b. NH3
d. SO4 ^2 -
a. HPO4 ^ 2 -
Explanation:
Acid is a compound which ionizes to produce hydrogen ions. The Ph value for acid is below 7. Base is a compound which ionizes to produce hydroxide ions. The Ph value for base is above 7. The Conjugate base accepts a proton or releases a hydrogen ion.