Answer: The number of moles of excess reagent left is 0.750 moles
Explanation:
The number of moles is calculated by using the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
For KI:Given mass of [tex]KI[/tex] = 249 g
Molar mass of [tex]KI[/tex] = 166 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of KI}=\frac{249g}{166g/mol}=1.5mol[/tex]
For [tex]Pb(NO_3)_2[/tex]:Given mass of [tex]Pb(NO_3)_2[/tex] = 496.5 g
Molar mass of [tex]Pb(NO_3)_2[/tex] = 331 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of }Pb(NO_3)_2=\frac{496.5g}{331g/mol}=1.5mol[/tex]
The given chemical equation follows:
[tex]2KI+Pb(NO_3)_2\rightarrow 2KNO_3+PbI_2[/tex]
By stoichiometry of the reaction:
If 2 moles of KI reacts with 1 mole of lead(II) nitrate
So, 1.5 moles of KI will react with = [tex]\frac{1}{2}\times 1.5=0.75mol[/tex] of lead(II) nitrate
As the given amount of lead(II) nitrate is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.
Thus, KI is considered a limiting reagent because it limits the formation of the product.
Moles of excess reactant ([tex]Pb(NO_3)_2[/tex]) left = [1.5 - 0.75] = 0.750 moles
Hence, the number of moles of excess reagent left is 0.750 moles
Identifying Conditions for Natural Selectlon
What are the conditions required for natural selection? Check all that apply.
Answer:
reproduction, variation in fitness, heredity, variation in individual characters
Al2S3 + 6H20 + 2Al(OH)2 + 3H2S
How many TOTAL number mole to mole ratios will there be total?
Answer:
the correct answer is 23:19
Calculate the volume of this regular solid.
What is the volume of the rectangular prism?
1
6 cm
5 cm
9 cm
This graph represents a population of molecules in a gas versus the distribution of the average velocity(speed) of its molecules in that population. Assume all molecules to be of the same mass. In reading the graph, it is important to note three things. One, is the most probable speed is at the peak of the curve. Secondly, the most probable speed increases as the temperature increases (so shift to the right), and the distribution broadens as it increases.
On the graph, indicate the average kinetic energy of the population.
Explain your answer.
What part of the graph indicates the temperature of the sample?
Explain your answer.
Sketch a curve that represents the distribution of molecules at a temperature below the one shown. Label it as T2. Describe both T and T2 in terms of their average kinetic energy. Be specific and detailed.
Submit your answer below.
Answer:
Part A
Given that the graph is symmetrical and bell shaped, the average kinetic energy is given by the midline of graph, which corresponds to the common speed of the highest number of the population
Part B
The formula for the average kinetic energy, K.E. = (3/2)·(R/NA)·T
Therefore, the part of the graph that indicates the temperature of the sample is the average kinetic energy. K.E.
Part C
At a lower temperature, the heat is less evenly distributed and we have the distribution T2 higher than T1
Please see the attached graph created with MS Visio
Explanation:
A doctor is testing a new medication and he doesn’t tell the people in the study about the possible side effects of the medicine. He is _____.
In the titration of a solution of Sodium hydroxide, an acid titrant was prepared by diluting 125.0 mL of 10.00 mol/L Nitric acid into enough distilled water to make 500.0 mL of solution. 30.0 mL of the base was measured, and in the titration, 16.74 mL of the acid titrant was needed to neutralize. Determine the concentration of the Sodium hydroxide.
Answer:
1.395M NaOH
Explanation:
Sodium hydroxide, NaOH, reacts with nitric acid, HNO3, as follows:
NaOH + HNO3 → NaNO3 + H2O
Where 1mol of NaOH reacts with 1mol of HNO3
To solve this question we must find the concentration of the titrant. With the concentration and the needed acid we can find the moles of HNO3 added = moles NaOH in the solution. With the moles of NaOH and its volume we can find its concentration as follows:
HNO3 concentration:
10.00mol/L HNO3 * (125.0mL/500.0mL) = 2.500M HNO3
Moles HNO3 = Moles NaOH:
16.74mL = 0.01674L*(2.500mol/L) = 0.04185 moles HNO3 = Moles NaOH
Concentration NaOH:
0.04185 moles / 0.0300L =
1.395M NaOH
Cells can regulate different processes in two ways. They can turn on and off the genes that make enzymes, or they can
A)
increase the activation energy of a reaction.
B)
increase the amount of energy needed to carry out the preferred process.
C)
regulate the enzymes that are already made.
D)
decrease the amount of energy needed to carry out the preferred process.
Answer:
im pretty sure its d
Explanation:
1
A coil of wire with an iron inside
becomes an? when there is
current.
Enter your answer
Answer:
A magnet
Explanation:
PLEASE HELP QUICK
The graph shows the distribution of energy in the particles of two gas samples at different temperatures, T1 and T2. A, B, and C represent individual particles.
Based on the graph, which of the following statements is likely to be true? (3 points)
Particle A is more likely to participate in the reaction than particle B.
Particle C is more likely to participate in the reaction than particle B.
The number of particles able to undergo a chemical reaction is less than the number that is not able to.
More gas particles participate in the reaction at T2 than at T1.
Answer:
Okay, I think I may actually have an answer for you. I would go with C, "The number of particles able to undergo a chemical reaction is less than the number that is not able to."
Explanation:
I just took a quiz with a similar question, and B is the only gas particle that is able to react. This cancels out all the other answers, as A and B are obviously incorrect based on that information, and it rules out D because T1 is the only sample with a particle able to react. I hope this helps!
Answer:
C is the right answer
Explanation:
is kcn a ternary ionic compound?
Answer:
The given molecule is KCN.
Is it a ternary ionic compound?
Explanation:
A ternary ionic compound is one that consists of at least one polyatomic ion/radical.
In the given molecule,
the ions present are:
K+ and CN-.
CN- is a polyatomic acidic radical.
Hence, the given molecule is ternary ionic compound.
Which explains why the laws
motion are scientific laws?
O A. The theories of motion became laws after there was enough
evidence to prove they were true.
O B. The laws cannot be tested by experiments, but scientists know
that they are correct because they make sense mathematically.
c. The laws explain how objects move and are supported by
experimental evidence.
O D. The laws describe a wide range of observations of motion and can
be used to predict the motion of objects.
Did
Answer:
D
Explanation:
Scientific laws describe how things work with little to no exception. They do NOT provide an explanation to WHY something occurs.
Answer:
The answer is D because scientific laws describe how things work not why they happen.
Question: What happens with the electrons between two atoms in a polar covalent bond?
a) Electrons are equally shared
b) Electrons are transferred
c) Electrons are unequally shared
d) Electrons become mobile in a ‘sea of electrons’
Answer:
c) Electrons are unequally shared
PLS I REALLY NEED HELP DUE FODAY
For the reaction of hydrogen gas with iodine gas to make hydrogen iodide gas, H2 + 12 → 2HI, you have the following concentrations at equilibrium: [HQ] = 4.5647 x 10-3 M, [12] = 7.378 x 10-4 [HI] = 1.3544 x 10-2 M. M, and What is the equilibrium constant?
0.4997
0.54
46.33
54.47
Answer: The equilibrium constant for the reaction is 54.47
Explanation:
The equilibrium constant is defined as the ratio of the concentration of products to the concentration of reactants raised to the power of the stoichiometric coefficient of each. It is represented by the term [tex]K_{eq}[/tex]
The given chemical equation follows:
[tex]H_2+I_2\rightleftharpoons 2HI[/tex]
The expression for equilibrium constant will be:
[tex]K_{eq}=\frac{[HI]^2}{[H_2][I_2]}[/tex]
We are given:
[tex][HI]_{eq}=1.3544\times 10^{-2}M[/tex]
[tex][H_2]_{eq}=4.5647\times 10^{-3}M[/tex]
[tex][I_2]_{eq}=7.378\times 10^{-4}M[/tex]
Putting values in above expression, we get:
[tex]K_{eq}=\frac{(1.3544\times 10^{-2})^2}{(4.5647\times 10^{-3})(7.378\times 10^{-4})}\\\\K_{eq}=54.47[/tex]
Hence, the equilibrium constant for the reaction is 54.47
HELPPP 50 POINTS
How are the things people are
doing helpful to them and harmful to them?
In a polar molecule, the partial positive charge on one molecule is attracted toward the partial _____ charge on a nearby molecule.
Answer:
negative
Explanation:
Opposite charges attract. Therefore the partial positive charge will be attracted to the partial negative charge
relate the intermolecular forces in hydrocarbons to their physical properties and uses
The physical properties of alkenes and alkynes are generally similar to those of alkanes or cycloalkanes with equal numbers of carbon atoms. Alkynes have higher boiling points than alkanes or alkenes, because the electric field of an alkyne, with its increased number of weakly held π electrons, is more easily distorted, producing stronger attractive forces between molecules.
Aqueous sulfurous acid decomposes into sulfur dioxide gas and liquid water. Write a chemical equation for this reaction.
Answer:When trying to concentrate the solution by evaporation to produce waterless sulfurous acid it will decompose
Explanation:
Explanation:
here's the answer to your question
Need help asap please!
Which contributes to the polarity of a water molecule?
A. a linear shape along with strong covalent bonds
B. deflection of hydrogen atoms by lone pairs of electrons
C. no difference in the electronegativity of oxygen and hydrogen
D. hydrogen bond formation between water molecules
Answer:
B
Explanation:
because polarity of the water molecules is due to the B. deflection of the hydrogen atoms by the lone pair of electrons.
Answer:
B
Explanation:
. A circuit is set up with two parallel resistors, each of a resistance of 250Ω. a. What is the total resistance for this circuit?
Answer:
125 ohms
Explanation:
since they're parallel we do
1/total resistance = (1/250 ohms) + (1/250 ohms)
then you get 2/250 ohms
then you flip it so it's equal to total resistance/1
250÷2= 125
Additional Activities
Direction: Sharpen your understanding in projectile motion. Calculate the maximum height reached and the horizontal range of the given launched angles and initial velocity of a projectile. You may opt to use the Projectile Motion Simulation with Air Friction by AERDEMIR which can be downloaded via Play Store for free.
1. To use the simulator, set the given values as shown in the left.
Start Angle = Launched Angle = refer to the table Start Velocity = Initial Velocity = 20 m/s
Change the gravitational acceleration to 9.8 only Delete the values in Air Density and Drag Coefficient
2. Deactivate the friction force by tapping the icon indicated in the above image.
The maximum height of an object, given the initial launch angle and initial velocity is found with:
h = v2 is in2θi 2g
h = v i 2 sin 2 θ i 2 g.
when potassium chloride is dissolved in water *
a)heat is given off
b)heat is taken in
c)temperature stays same
Answer:
Option B . heat is taken in
Answer:
B
Explanation:
we need to eat,drink,and sleep to be healthy
A solution has a [H3O+] of 1 × 10−3 M. What is the [OH−] of the solution?
A. 11 M
B. 14 M
C. 1 × 10−14 M
D. 1 × 10−11 M
Answer:
D. 1x10⁻¹¹ M
Explanation:
For any given aqueous solution the following formula is true:
1x10⁻¹⁴ = [H₃O⁺] * [OH⁻]
1x10⁻¹⁴ is the ion-product constant of water, Kw.
We input the given value of [H₃O⁺]:
1x10⁻¹⁴ = 1x10⁻³ * [OH⁻]
And solve for [OH⁻]:
[OH⁻] = 1x10⁻¹¹ M
Thus the correct answer is option D. 1x10⁻¹¹ M.
Answer:
D. 1x10⁻¹¹ M
Explanation:
I took the test :)
How much heat energy is released if 24.3 g of gold is cooled from 2580.0°C to room temperature (20.0°C)?
Answer:
-8024.832 J
Explanation:
The amount of heat energy lost or released, Q, can be calculated thus;
Q = m × c × ∆T
Where;
Q = amount of heat lost (J)
m = mass of substance (g)
c = specific heat capacity (J/g°C)
∆T = change in temperature (°C)
According to this question,
Q = ?
m = 24.3 g
c of Gold = 0.129 J/g°C
∆T = 20°C - 2580.0°C = -2560°C
Using Q = m × c × ∆T
Q = 24.3 × 0.129 × -2560°C
Q = -8024.832 J
This means that 8024.832 J of energy is lost or released.
What is20 grams of HNO^3
63.01284*20=1260.568
Explanation:
Here are the answers for both of the question you send :)
hope this helps you to understand:)
How many moles of H2O
moles of H2O are needed to produce 55.7 moles of H2?
Answer: 55.7 moles of [tex]H_2O[/tex] are needed to produce the given amount of [tex]H_2[/tex]
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass.
The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Given values:
Moles of [tex]H_2[/tex] = 55.7 moles
The chemical equation for the decomposition of water follows:
[tex]2H_2O\rightarrow 2H_2+O_2[/tex]
By the stoichiometry of the reaction:
If 2 moles of hydrogen gas is produced from 2 moles of water
So, 55.7 moles of hydrogen gas will be produced by = [tex]\frac{2}{2}\times 55.7=55.7mol[/tex] of water
Hence, 55.7 moles of [tex]H_2O[/tex] are needed to produce the given amount of [tex]H_2[/tex]
Taking into account the reaction stoichiometry,
Reaction stoichiometryIn first place, the balanced reaction is:
2 H₂O → 2 H₂ + O₂
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
H₂O: 2 molesH₂: 2 molesO₂: 1 moleMoles of H₂O requiredThe following rule of three can be applied: if by reaction stoichiometry 2 moles of H₂ are produced from 2 moles of H₂O, 55.7 moles of H₂ are produced from how many moles of H₂O?
[tex]moles of H_{2} O=\frac{55.7 moles of H_{2}x 2 moles of H_{2} O}{2 moles of H_{2}}[/tex]
moles of H₂O= 55.7 moles
Finally, 55.7 moles of H₂O is requiredto produce 55.7 moles of H₂.
Learn more about the reaction stoichiometry:
brainly.com/question/24741074
brainly.com/question/24653699
Ethanol has a heat capacity of 2.46 Jig 'c. If 50 g of ethanol has a temperature of 30°C and a piece of hot Copper is added to the ethanol causing the
temperature to increase to 70°C. What is the amount of heat absorbed by the ethanol?
Explanation:
there it is fella tried on ma own consciousness
Calculate the pressure kPa of 0.421 mole of helium gas at 254 degree celsius when it occupies a volume of 3.32 L.
There is a close relation between forest
and wildlife.
Answer:
habitat
Explanation:
wild animal need
what do u mean by change in state of matter?define it.
Answer:
The mode of changing from one state of matter into another state and back to the former or original state is called change in state of matter .
hope it is helpful to you
Answer:
change in one state from another and back in its own original is known as change in state of matter
Which will boil faster distilled water or salt water and why?
Answer:
The distilled water will be boiled faster as it does not contain any non - volatile solute.
- The salty water contains different non - volatile salts in it.
- Due to the presence of these salts, its vapour pressure will be decreased and boiling point will be elevated.
- So, salty water will take more time to boil.
- On the other hand, distilled water does not have any such solute and due to this its vapour pressure will not be affected.
- Hence, it will boil fast than salty water.