Answer:
(I) [tex] m_{ZnCl_{2}} = 34.07 g [/tex]
(II) [tex] \% y = 176.4 \% [/tex]
(III) The presence of impurities in the 32.70 g of zinc will support the student's percentage yield.
Explanation:
The reaction is:
Zn + 2HCl → ZnCl₂ + H₂
(I) To find the number of moles of ZnCl₂ we need to calculate the number of moles of the reactants.
[tex] n_{Zn} = \frac{m}{A} [/tex]
Where:
m: is the mass
A: is the standard atomic weight
[tex] n_{Zn} = \frac{32.70 g}{65.38 g/mol} = 0.50 moles [/tex]
[tex] n_{HCl} = \frac{18.23 g}{36.458 g/mol} = 0.50 moles [/tex]
If 1 mol of Zn reacts with 2 moles of HCl, the number of moles of Zn needed to react with 0.50 moles of HCl is:
[tex] n_{Zn} = \frac{1 mol Zn}{2 moles HCl}*0.50 moles HCl = 0.25 moles [/tex]
Then, the limiting reactant is HCl. Now, we can find the number of moles of ZnCl₂ by knowing that 2 moles of HCl produce 1 mol of ZnCl₂.
[tex] n_{ZnCl_{2}} = \frac{1 mol ZnCl_{2}}{2 moles HCl}*0.50 moles = 0.25 moles [/tex]
Finally, the mass of ZnCl₂ that he has produced is:
[tex] m_{ZnCl_{2}} = n_{ZnCl_{2}}*M = 0.25 moles*136.286 g/mol = 34.07 g [/tex]
(II) The percentage yield can be found with the following equation:
[tex] \% y = \frac{m_{e}}{m_{t}} \times 100 [/tex]
Where:
[tex] m_{e}[/tex]: is the experimental mass = 60.1 g
[tex] m_{t}[/tex]: is the theoretical mass = 34.07 g
Hence, the percentage yield is:
[tex] \% y = \frac{60.1 g}{34.07 g} \times 100 = 176.4 \% [/tex]
(III) The presence of impurities in zinc will explain why the percentage yield is greater than 100% because the mass of the impurities will make the mass of zinc bigger than its mass without impurities. If there were no impurities in the zinc, its mass would be smaller and thus the percent yield.
I hope it helps you!
I have 3 questions that I will need help from you. 1. The weight of a millimeter of (NH4)2 HPO4 is? 2. How many moles of alanine, C3H7NO2 are there in 159g of alanine? And 3. Nitric acid is a very important industrial chemical. 1.612 * 10^10 pounds of it were produced in 1992. If the density of nitric acid is 12.53 pounds/gallon. What volume would be occupied by this quantity. (1 gallon =3.7854liters)
Answer:
1. m(NH₄)₂HPO₄ = 1.62 g
2. molesC₃H₇NO₂ = 1.79 moles
3. V = 4.87x10⁹ L
Explanation:
These questions are pretty easy to solve, using the correct expressions and formula.
1. To do this, we just need the density of the (NH₄)₂HPO₄. In this case, the reported density is 1.62 g/mL, therefore:
d = m/V (1)
Where:
d: density (g(mL)
m: mass of the compound (g)
V: volume of the compound (mL)
As we already have the volume, we can solve for m:
m = d * V (2)
m = 1.62 * 1
m(NH₄)₂HPO₄ = 1.62 g2. To do this, we need the atomic weights of each element that composes the alanine.
C: 12 g/mol; H: 1 g/mol; N: 14 g/mol; O: 16 g/mol
With these atomic weight, let's determine the molar mass of alanine:
MM C₃H₇NO₂ = 3(12) + 7(1) + 14 + 2(16) = 89 g/mol
Now to get the moles, we use the following expression:
moles = m/MM (3)
moles = 159 / 89
molesC₃H₇NO₂ = 1.79 moles3. We have the mass and density of the nitric acid, we just solve for Volume from expression (1) of part 1:
V = m/d (3)
V = 1.612x10¹⁰ pounds / 12.53 pounds/gallons
V = 1.287x10⁹ gallons
Converting this to liters:
V = 1.287x10⁹ * 3.7854
V = 4.87x10⁹ LHope this helps
Can someone pleasee help me with this asap!! Im struggling
4a. D - The last number in the configuration represents the group, in this case 3, and the number of shells represent the period, which is also 3.
4bi. Rubidium metal reacts very rapidly with water to form a colourless solution of rubidium hydroxide (RbOH) and hydrogen gas (H2). The resulting solution is basic because of the dissolved hydroxide. The reaction is very exothermic and explosive.
4bii. Lithium is smaller in size than potassium . so valence electrons are more tightly held in Li than K. Due to larger size of K the valence electrons are loosely held and easy to remove the electron from K. Hence K is more reactive.
____ are pieces of information that describe the appearance of the cell's content.
I think the answer is organelles.
The power of the crane was 68600 W
Caculate the time taken for the crane to do 3430000 J of work
Give the unit
Answer:
t = 50 s
Explanation:
P = W/t
Solving for t,
t = W/P = (3430000 J)/(68600 Watts)
= 50 s
Note: 1 Watt = 1 J/s
According to the question, the time that is taken by the crane which has the power of 68600 W to 3430000 J of work is 50 seconds.
What is Power?Power may be defined as the amount of energy that is significantly transmitted or converted per unit of time. In a more simple sense, it is also characterized as the measure of the rate of doing work.
According to the question,
The power of the crane = 68600 W.
The amount of work that the crane has to do = 3430000 J.
Time may be calculated with the help of the following formula:
Power = Work/time.Time = Work/power = 3430000 J/68600 W = 50 seconds. (where 1 W = 1 J/sec).Therefore, according to the question, the time that is taken by the crane which has the power of 68600 W to 3430000 J of work is 50 seconds.
To learn more about Power, refer to the link:
https://brainly.com/question/1634438
#SPJ2
Which characteristic most likely identifies an object with a small volume and a large mass?
A.
high temperature
B.
low pressure
C.
low viscosity
D.
high density
Answer:
high density is the ans because density is the mass per unit volume.if mass increases density also increases.
Answer:
High temperature is an object with a small volume and a large mass.
Answer is no A
I need help everyone
Answer:
The answer is D
The last one
If 500 g of iron absorbs 184,000 J of heat, what will be the change in temperature?NEED THE ANSWER AS SOON AS POSSIBLE! :)
Answer:
Is this the full question?
How many grams of NaNO3 can be dissolved in 200mL of water at 40 degrees Celsius?
Group of answer choices
200 grams
210 grams
100 grams
105 grams
Answer:
I think the answer is, 100.
Explanation:
but i dont know try
Which statement is true about the square pyramid below?
32 in
| 29 in
The base has an area of 464 square inches.
The base has an area of 928 square inches.
Each of the lateral faces has an area of 464 square inches.
Each of the lateral faces has an area of 928 square inches.
Answer:
C) Each of the lateral faces has an area of 464 square inches.
Explanation:
Have an actual answer
Answer:
CCCCCCCCCCCCCCCCCCC
Explanation:
Each of the lateral faces has an area of 464 square inches.
When pumping air into a tire, you have to pull back on the pump plunger to fill the pump with air. This increases the volume of the air inside the pump. This increase in volume has what effect on the gases inside the pump?
Question 9 options:
the gas molecules inside the pump are able to spread out more which decreases the pressure of the gas.
the gas molecules inside the pump get compressed and packed closer together which decreases the pressure of the gas.
the gas molecules inside the pump are able to spread out more which increases the pressure of the gas.
the gas molecules inside the pump get compressed and packed closer together which increases the pressure of the gas.
Answer:
Pulling back on the plunger allows you to put in more air into the pump and the more air you have inside a fixed volume, the greater the pressure becomes. (D)
HELP ME PLS
What is the mass of a water molecule if the hydrogens each have one neutron and the oxygen has eight neutrons?
a. 10
b. 12
c. 16
d. 20
Answer:
H2O
=(1×2)+(8)
=20
Explanation:
We have 1 Hydrogen(H) and 8 Oxygen(O)neutrons . Following the molecule formula, H2O, which means we have 2 Hydrogen that needs to times with 1 neutron;and we have only 1 Oxygen which has 8 neutrons. So 2 (H) have to times 1 and 1(O) have to times 8.
Plz Answer this if you Answer this right you will get brainliest
Don't Answer this question if you don't know you will be reported
Reaction 1 :-
AlZn²⁺Zn²⁺AlReaction 2 :-
LiAl³⁺Al³⁺Li____________________what type of heat is it when a handle of a saucepan get hot when it is on the stove
Answer:
A conduct heat
Explanation:
because in cooking burners on stove will conduct heat energy to the bottom of the pan sitting on top of it. From there, the pan conducts heats to it content.
Which is NOT true of the Sc3+ ion?
Multiple choice question.
A)
It is a scandium ion with three positive charges.
B)
It was formed by the loss of 4s and 3d electrons.
C)
It has the same electron configuration as Ar.
D)
It is considered to be a different element than a neutral Sc atom.
Answer:
D. It is considered to be a different element than a neutral Sc atom.
The statement i.e. not true of the Sc3+ ion is that it is considered to be a different element than a neutral Sc atom.
The statements that should be considered as true regarding the Sc3 + ion is as follows:
It represents the scandium ion having 3 positive charges.It is created via the loss of 4s & 3d electrons. And, it contains the similar configuration as treated as Ar.Therefore we can conclude that the statement i.e. not true of the Sc3+ ion is that it is considered to be a different element than a neutral Sc atom.
Learn more: brainly.com/question/362440
What form of pollution can lichens be a good indicator of?
Answer:
Lichens can be used as air pollution indicators, especially of the concentration of sulphur dioxide in the atmosphere. Lichens are organisms that grow in exposed places such as rocks or tree bark. They need to be very efficient at absorbing water and nutrients to grow there.
que es la nanotecnologia ?
porfis lo nesecito urgente para antes de las 10
Answer:
Se aclama la nanotecnología por tener el potencial de aumentar la eficiencia del consumo de energía, ayudar a limpiar el medio ambiente y resolver los principales problemas de salud. Se dice que puede aumentar masivamente la producción de fabricación a costos significativamente reducidos.
espero que esto ayude
A gas with a volume of 250 mL at a temperature of 293K is heated to 324K. What is the new volume of the gas?
Answer:
The new volume of the gas is 276.45 mL.
Explanation:
Charles's law indicates that 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.
Charles's law is a law that mathematically says that when the amount of gas and pressure are kept constant, the quotient that exists between the volume and the temperature will always have the same value:
[tex]\frac{V}{T} =k[/tex]
Analyzing an initial state 1 and a final state 2, it is satisfied:
[tex]\frac{V1}{T1} =\frac{V2}{T2}[/tex]
In this case:
V1= 250 mLT1= 293 KV2= ?T2= 324 KReplacing:
[tex]\frac{250 mL}{293 K} =\frac{V2}{324 K}[/tex]
Solving:
[tex]V2=324 K*\frac{250 mL}{293 K}[/tex]
V2= 276.45 mL
The new volume of the gas is 276.45 mL.
Which general formula represents the homologous series of hydrocarbons that includes the compound
2-heptyne?
(1) Cn H2n-6
(2) Cn H2n-2
(3) Cn H2n
(4) Cn H2n+2
the general formular is cnH2n-2
Which of the following statements are true?
a.
Visible light is composed of different wavelengths.
b.
The shorter the wavelength, the more refraction occurs.
c.
Different wavelengths refract at different angles.
d.
All of the above.
Helpp!! Please it’s balancing equations and I really need help in it it’s so hard theirs two other parts if you can help with those too:))
PLEASE HELP ME ASAP!!! 10 POINTS!!
The three equations below represent nuclear fission and nuclear fusion reactions. For each equation, tell whether fission or fusion has occurred and write the missing term in the equation.
A) ²³⁵₉₂ U+n→⁹⁵₃₈Sr+____+2n
B) ³₁H+²₁H→⁴₂H+____
C) ____+n→⁹²₃₉Y+¹⁴⁰₅₃I+2n
Explanation:
A) fission: Iodine-140 (atomic number = 53)
B) fusion: 1 neutron
C) fission: Uranium-233 (atomic number = 92)
What are the two products of every neutralization reaction?
Group of answer choices
Salt and Water
Acid and Base
Acid and Hydrogen Gas
Acid and Hydroxide
Answer:
Explanation:
c
In order for photosynthesis to happen, plants need radiant energy and which of the
following reactants?
A
Glucose sugar and water
B
Oxygen and water
с
Carbon dioxide and water
D
Oxygen and glucose sugar
Answer:
the answer is c carbon dioxide and water
Which of the following is a method for measuring energy in food?
A. reading the label
B. filtration
C. chromatography
D. calorimetry
Why is water often used as the main ingredient in cosmetics?
Answer:
Water forms the basis of almost every type of cosmetic product, including creams, lotions, makeup, deodorants, shampoos and conditioners. Water plays an important part in the process, often acting as a solvent to dissolve other ingredients and forming emulsions for consistency.
Explanation:
Water forms the basis of almost every type of cosmetic product, including creams, lotions, makeup, deodorants, shampoos and conditioners. Water plays an important part in the process, often acting as a solvent to dissolve other ingredients and forming emulsions for consistency.
how are fossils discovered
please help me I have no idea what this is
What is the elevation of point x on rock mountain ( Ik it's blury but please help for 30 points ) ty
Explanation:
A contour map shows two locations, X and Y, 5 kilometers apart. The elevation at location X is 800 meters and the elevation at location Y is 600 meters.
3.00 L of a gas is collected at 150 K and then allowed to expand to
15.0 L. What must the new temperature be in degrees C in order to
maintain the same pressure (as required by Charles' Law)?
Answer:
477 ºC
Explanation:
on an isobaric process, an increase on the volume implies an increase on the temperature:
V1/T1 = V2/T2
T2 = V2T1/V1 = 15.0 L×150 K/3.00 L = 750 K
t/ºC = T/K - 273 = 750 K/K - 273
t = 477 ºC
V1: initial volume
T1: initial temperature
V2: final volume
T2: final temperature
A scientific is a statement that explains what always happens under very specific conditions.
O hypothesis
conclusion
a
theory
O
law
Answer:
law
Explanation: