To achieve the highest return during recrystallization of a given solid, one must: Group of answer choices Add the minimum amount of boiling solvent necessary to dissolve the solid to be crystallized. Add an excess amount of cold solvent necessary to dissolve the solid to be crystallized. Add the minimum amount of cold solvent necessary to dissolve the solid to be crystallized. Add an excess amount of boiling solvent necessary to dissolve the solid to be crystallized.
Answer:
Option A
Explanation:
Addition of too much of solvent will make the solution dilute due to which the crystals will not form. Hence option D is incorrect
On the other hand adding a minimum amount of boiling solvent will give a saturated solution for recrystallization. Hence, option A is incorrect
Addition of cold solvent will lower the rate of formation of crystals. Hence, both option B and C are incorrect
Submit your one paragraph essay about disability insurance
Answer:
Disability insurance is financial protection for your most valuable asset — the ability to work and earn an income. So why is it so commonly overlooked and misunderstood?
Homeowners insurance protects where you live. Car insurance protects what you drive. Health insurance protects your well-being.
But what protects your ability to work and earn an income? After all, that's what allows you to pay for all of the above.
To protect yourself against the risk of losing your paycheck due to injury or illness, there's disability insurance. In this article, we cover everything you need to know about this important, yet often overlooked type of insurance for your income.
Disability insurance definition
Disability insurance is a type of coverage that replaces a portion of your monthly income if injury or illness prevents you from working. It provides financial security for you and any loved ones who may depend on your most valuable asset — your ability to earn a paycheck. You may also hear disability insurance referred to as disability income insurance or income protection.
Explanation:
0.329 M copper (II) nitrate was reacted with 0.528 M potassium carbonate as follows: Cu (NO subscript 3 )subscript 2 italic (a q italic )space plus space straight K subscript 2 CO subscript 3 italic (a q italic )rightwards arrow CuCO subscript 3 italic (s italic )space plus space 2 thin space KNO subscript 3 italic (a q italic )Determine the percent yield if 163.9 mL of each reactant were allowed to react, and a mass of 4.883 g of solid were obtained.
Answer:
73.33% is the percent yield
Explanation:
Percent yield is defined as:
Actual yield (4.883g) / Theoretical yield * 100
Based on the reaction:
Cu(NO₃)₂(aq) + K₂CO₃(aq) → CuCO₃(s) + 2KNO₃(aq)
1 mole of copper nitrate reacts per mol of potassium carbonate.
To solve this question we must find limiting reactant. With limiting reactant we can find the theoretical moles of solid produced and its mass as follows:
Moles Cu(NO₃)₂:
0.1639L * (0.329mol / L) = 0.0539 moles
Moles K₂CO₃:
0.1639L * (0.528mol / L) = 0.0865 moles
As the reaction is 1:1, the limiting reactant is Cu(NO₃)₂.
1 mol of Cu(NO₃)₂ produces 1 mol of CuCO₃. That means theoretical moles produced are 0.0539 moles. And the mass is:
Mass CuCO₃ -Molar mass: 123.55g/mol-
0.0539 moles * (123.55g / mol) = 6.659g of CuCO₃ is the theoretical mass
And percent yield:
4.883g / 6.659g * 100
73.33% is the percent yieldWhen 15. 3 g NaCl reacts with 81.70 g Pb(NO3)2, sodium chloride is the limiting reactant, according to the balanced equation below. How many grams of lead (II) nitrate will remain after the reaction stops?
2 NaCl + 1 Pb(NO3)2 → 2 NaNO3 + 1 PbCl2
Answer:
[tex]m_{Pb(NO_3)_2}^{leftover}=38.34g[/tex]
Explanation:
Hello there!
In this case, given the chemical reaction by which the sodium chloride reacts with lead (II) nitrate and the former is the limiting reactant, it is possible to calculate the mass of lead (II) nitrate that are actually consumed according to the 2:1 mole ratio between them:
[tex]m_{Pb(NO_3)_2}=15.3gNaCl*\frac{1molNaCl}{58.44gNaCl}*\frac{1molPb(NO_3)_2}{2molNaCl} *\frac{331.21gPb(NO_3)_2}{1molPb(NO_3)_2} \\\\m_{Pb(NO_3)_2}=43.36gPb(NO_3)_2[/tex]
Thus, the leftover of lead (II) nitrate is:
[tex]m_{Pb(NO_3)_2}^{leftover}=81.70g-43.36g\\\\m_{Pb(NO_3)_2}^{leftover}=38.34g[/tex]
Best regards!
What mass of iron(III) oxide will be formed if 9.30 L of oxygen at STP react with excess iron?
Answer:
12
Explanation:
because that plot and the iron
Object X carries a net negative charge. Danny touches object X and all of the excess negative charge leaves it. Danny effectively grounds object X by touching it.
Answer: B.) Object X Is A Conductor
Explanation: Since object X was able to lose all of its charge by being grounded, this means that its charges were able to move about freely. This strongly suggests that object X is a conductor. If object X had been an insulator, the ground would have had virtually no effect on its net charge.
Rubbing alcohol and vegetable oil soluble on insoluble?
Which of the following accurately describes the function of the muscular
system?
O A. To prevent and fight disease
B. To provide support for the body
C. To get rid of wastes and excess water
D. To allow the body to move
in which block does chlorine lies
Answer:
P-block
Explanation:
Chlorine
Atomic number (Z) 17
Group group 17 (halogens)
Period period 3
Block p-block
Answer:
What does "in which block does chlorine lies"? That question has no way to answer it because there is no question content lol
Explanation:
7. Calculate moles of H2 needed to form 2.25 moles HCl in the reaction H2 + Cl2==>2HCl
Answer:
1.125 moles
Explanation:
2mole of HCl produced 1mole of H2
2.25moles of HCl will produce x moles
cross multiply
2x=™1×2.25
x= 2.25÷2
x=1.125mole
Please someone answer this asap
Answer:
b or c but I would just pick c
Answer:
C
Explanation:
Sun is an energy source not a matter.
PLEASE HELP WILL MARK BRAINLEST!!!!
Answer: c????????
Explanation:
very small particles of solids and liquids suspended in air are called
Answer:
aerosols
Explanation:
PLEASE HELP Describe at least two advantages and two disadvantages of using hydropower as a
source of energy.
PLS ONLY ANSWER THE FULL QUESTION ON HERE DO NOT SEND A LINK FOR ME TO CLICK!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:
Advantage: Hydropower is a fueled by water, so it's a clean fuel source.
Advantage: It is a domestic source of energy in the US.
Disadvantage: Fish populations can be impacted if fish cannot migrate upstream past impoundment dams to spawning grounds or if they cannot migrate downstream to the ocean.
Disadvantage: Hydropower plants can be impacted by drought. When water is not available, the hydropower plants can't produce electricity.
Explanation:
In both industry and research there are often times when one particular component of a mixture needs to be separated from a solution. Maybe it is a rare metal that is dissolved in a mixture of minerals. Maybe it is a particular protein from lysed plant cells. If the desired component is volatile, distillation could be used. But if the goal is to separate ions in solution, fractional precipitation is preferred.
a. True
b. False
Answer:
a. True
Explanation:
Distillation process is a process that is used to separate the components or the substances from the liquid mixtures by using selectively boiling and condensation.
While fractional precipitation is a process which separates the ions from solution based on the different solubilities.
Therefore, the answer is true.
My swimming pool is rectangular (16 feet by 34 feet) and has a depth of 6 feet. Lets imagine that my pool water is full to the top and is heated by a laser that emits photons with a wavelength of 520 nm. The starting temperature of my pool is a chilly 52 degrees Celsius. How many moles of photons would be required to heat the pool to a balmy 80 degrees Celsius
Answer:
Number of moles of photons required = 5.04 × 10⁴ moles
Explanation:
The energy of a photon can be calculated from Planck's equation E = hc/λ
Where h = 6.63 × 10-³⁴ Js and c, the velocity of light = 3.0 × 10⁸ m/s
Energy of one mole of photons = N₀ × hc/λ
wavelength of photon, λ = 520 nm = 5.20 × 10-⁷ m
Energy of one mole of photons = 6.02 × 10²³ × 6.63 × 10−³⁴ × 3 × 10⁸/5.20 × 10-⁷
Energy of one mole of photons = 2.30 × 10⁵ J/mol
Energy required to raise the temperature of a given mass of a substance, E = mcΔT
Where m is mass of substance, c is specific heat capacity, ΔT is temperature difference
Mass ofnwternin the pool = volume × density
Volume of water = Volume of swimming pool
Volume of water = 16 × 34 × 6 ft³ = 3264 ft³
1 ft³ = 28316.8 cm³; 3264 ft³ = 28316.8 × 3264 = 92426035.2 cm³
Density of water = 1 g/cm³
Mass of water = 92426035.2 cm³ × 1 g/cm³ = 92426035.2g
ΔT = 80°C - 50°C = 30°C, c = 4.18 J/g/K
Energy required to raise 92426035.2 g water by 30° C = 92426035.2 × 4.18 × 30
Energy required = 1.16 × 10¹⁰ J
Hence, number of moles of photons required = 1.16 × 10¹⁰ J/2.30 × 10⁵ J/mol
Number of moles of photons required = 5.04 × 10⁴ moles
Calculate the mass of 0.900 mol of lithium thiocyanate.
Answer:
58.6 g.
Explanation:
Hello there!
In this case, since the molecular formula of lithium thiocyanate is LiCNS and therefore its molar mass is 65.1 g/mol, it possible to perform the calculation of the mass of 0.900 moles of this substance by recalling the following equivalence statement:
1 mol = 65.1 g.
Thereby, we can calculate the required mass as shown below:
[tex]0.900mol*\frac{ 65.1g}{1mol}\\\\58.6 g[/tex]
Best regards!
a. Explain why the pie pans flew off the van de Graaf generator
b. Give a detailed explanation of why the rabbit fur and the plastic rod were attracted to each other after we rubbed them together but not before
c. Describe two things you could change to increase the force of electrical attraction between two objects (this is about Coluomb's Law).
Answer:
Static energy is an energy between two charges.
Explanation:
a). A van de Graff generator builds up a positive electric charge on the dome by separating the negative static electric charges from the positive static charge using a quickly moving belt. The positive charge collects on the large metal dome of the generator. When the charge builds up is large enough, a lighting like spark can shoot from the dome to a grounded discharge rod.
Like electric charges always repel each other, and oppositely electric charges will attract each other. When the aluminum pans are being charged by the van de Graff generator, then each of them attain the same positive polarity similar with the dome. Thus, positive charge starts to accumulate over the surface of each of the pie pan. Each aluminum pan repels the others. These repulsive forces between the pans are so strong that they succeed in overcoming the gravity force and thus the top of the pan is pushed away from the generator's dome.
b). Static electricity is produced by a concentration of negative and positive electric charges. Like charges pushes away each other while unlike charges pulls each other.
Objects generally have same numbers of positive charges as well as negative charges. And if there is any small imbalance in numbers of the charges on the object, it is charged.
Negative charges easily torn away from the materials like the fur or hair. Also, the negative charges are held on other materials like the plastics. If we rub a plastic rod with fur, the negative charges will get transferred from fur to rod. The rod gets negatively charged and the fur is positively charged. As a result, the rabbit fur and the plastic rod were attracted to each other.
c). Coulomb's law stated that :
[tex]$F=\frac{KQ_1Q_2}{d^2}$[/tex] .............(i)
where, [tex]$Q_1$[/tex] and [tex]$Q_2$[/tex] are the charges of two objects d is the distance between two objects.
As from the above equation, we can say that force of electrical attraction between two objects depends on the charges and the distance between objects.
1. The electrical force between two charged object is inversely proportional to the distance of separation between two objects.
Decreasing separation distance (d) between the objects will increase its attraction force.
2. And, increasing the charges of two objects(+ve and -ve) increases the force of attraction between two objects.
is scandium a transition metal?
Answer:no
Explanation:
Answer:
Scandium is a transition metal
Explanation:
Rank the following solutions from lowest to highest vapor pressure.
Rank from lowest to highest. To rank items as equivalent, overlap them.
10.0 g of potassium acetate KC2H3O2 in 100.0 mL of water
20.0 g of sucrose (C12H22O11) in 100.0 mL of water
20.0 g of glucose (C6H12O6) in 100.0 mL of water
Solution :
When non volatile solute is added to solvent, vapor pressure gets lowered.
Relative lowering in vapor pressure is given :
[tex]$\frac{P^0-P}{P^0}$[/tex] = [tex]$\text{mole fraction}$[/tex] of solute
[tex]$\frac{P^0-P}{P^0}=x_B$[/tex]
[tex]$P^0$[/tex] = vapor pressure of pure solvent
P = vapor pressure of solution
[tex]$x_B$[/tex] = mole fraction of solute
[tex]$x_B=\frac{n_B}{n_A+n_B}$[/tex]
[tex]$n_B $[/tex] = [tex]$\text{number of moles of solute}$[/tex]
[tex]$n_A$[/tex] = [tex]$\text{number of moles of solvent}$[/tex]
Number of moles [tex]$=\frac{\text{weight}}{\text{molecular weight}}$[/tex]
[tex]$\frac{P^0-P}{P^0}=\frac{w_B/M_B}{w_A/M_A+w_B/M_B}$[/tex]
[tex]$\approx \frac{w_B/M_B}{w_A/M_A}$[/tex]
1. For 10 g of [tex]$CH_3COOK$[/tex]
[tex]$CH_3COOK \rightarrow CH_3COO^- + K^+$[/tex]
Ions = 2
It will affect colligative property.
[tex]$\frac{P^0-P}{P^0} = \frac{i \times 10/98}{w_A/M_A}$[/tex]
Relative lowering in vapor pressure will be :
[tex]$=\frac{2 \times 10/98}{w_A/M_A}$[/tex]
[tex]$=\frac{0.20}{w_A/M_A}$[/tex]
2. For 20 g sucrose
Sucrose is non electrolyte, i = 1
[tex]$\frac{P^0-P}{P^0} = \frac{ 20/342}{w_A/M_A}$[/tex]
[tex]$=\frac{0.050}{w_A/M_A}$[/tex]
3. For 20 g of glucose.
Glucose is a non electrolyte, i = 1
[tex]$\frac{P^0-P}{P^0} = \frac{20/180}{w_A/M_A}$[/tex]
[tex]$=\frac{0.11}{w_A/M_A}$[/tex]
[tex]$w_A/M_A$[/tex] is same in all three solutions.
Hence, lowering in vapor pressure is maximum in [tex]$CH_3COOK$[/tex] and minimum is Sucrose.
Vapor pressure from lowest to highest.
10 g of [tex]$CH_3COOK$[/tex] < 20 g of glucose < 20 g of sucrose
The pressure exerted by vapor to the other gas is called vapor pressure.
The formula used to solve the question is as follows:-
[tex]\frac{P^o -P}{P^o}[/tex]
The water vapor depends on the following:-
Water pressureTemperature.After solving the equation, the correct sequence is as follows:-
[tex]CH_3COOK > GLUCOSE > SUCROSE[/tex]
For more information, refer to the link:-
https://brainly.com/question/22810476
Which of these space objects is the largest asteroid in the solar system?
Select one:
a. Pluto
b. Vesta
c. Ceres
d. Earth's Moon
Answer:
CERES is the latgest in the solar system
Explanation:
Write out and balance the chemical equation:
A solution of nickel (II) chloride reacts with a solution of potassium hydroxide
to produce solid nickel (II) hydroxide and a solution of potassium chloride.
Explanation:
NiCl2 + KOH = NiOH + KCl
since nickel is the primary element in nickel ii chloride, find the oxidation no of nickel in the compound and chlorine should have 2 as a subscription since the ii in the compound represents that nickel has an oxidation no of 2
how many moles of lithium are in 18.2 grams of lithium
Answer:
I think 2.6 sorry if its wrong
The number of moles of 18.3 grams of lithium is equal to 2.62 mol.
What is a mole?A mole can be defined as a metric unit that is used to evaluate a count of particles in the sample of a given substance. The particles counted are generally identical chemical entities, but they are individually distinct.
A mole is used for a large number of quantities of molecules, atoms, ions, or other specific particles. The number of chemical compounds or elements can be measured in the terms of moles.
The number of units of the chemical which are present in 1 mole is equal to 6.023 × 10 ²³ refers to Avogadro’s constant.
Given, the mass of lithium in the sample = 18.2 g
The mass of one mole of lithium = 6.94 g
6.94 grams of lithium has moles = 1 mol
18.2 g of lithium has moles of Li = 18.2/6.94 = 2.62 mol
Therefore, the moles in 18.2 g of Lithium is 2.62 mol.
Learn more about the mole, here:
brainly.com/question/26416088
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Mg + HCl -> MgCl2 + H2
When the equation is balanced what should the coefficient for magnesium chloride be
Explanation:
hope it helps you
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What is the difference between chemical change and physical change
Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.
CH3CH2OH can interact with
other like molecules through ___?
Answer: dispersion forces, dipole-dipole and hydrogen bonds
Explanation:
What is the total number of Joules lost when 10. grams of water at 80.°C is cooled to 60.°C?
Answer:
[tex]\boxed {\boxed {\sf 836.8 \ Joules \ lost}}[/tex]
Explanation:
Since we are given the mass and change in temperature, we should use the following formula for heat.
[tex]q= mc \Delta T[/tex]
In this formula, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.
We know the mass of the water is 10 grams. We will have to look up water's specific heat, because it is not given. It is 4.184 J/g °C.
Let's find the change in temperature. This is the difference of the final and initial temperature. The water started at 80 °C and cooled to 60°C.
ΔT= final temperature - initial temperature ΔT= 60° C - 80°C ΔT= -20 °CNow we have values for each variable.
m= 10 gc= 4.184 J/g°C ΔT= -20°CSubstitute the values into the formula.
[tex]q= 10 \ g * 4.184 \ J/g \textdegree C * -20 \textdegree C[/tex]
Multiply the first 2 numbers. The units of grams will cancel each other out.
[tex]q= 41.84 \ J/ \textdegree C * -20 \textdegree C[/tex]
Multiply again. This time, the degrees Celsius cancel.
[tex]q= -836.8 \ J[/tex]
A total of 836.8 Joules are lost.
How many grams of potassium carbonate are needed to make 300ml of a 4.5M solution?
Answer:
186.3g
Explanation:
4.5moles of K₂CO₃ is in 1000ml
? moles of K₂CO₃ is in 300 ml
(4.5 × 300)/ 1000 = 1.35 moles of K₂CO₃
1 mole of K₂CO₃ = (39 × 2) + 12 + (16 × 3) = 78 + 12 + 48 = 138g
1.35 moles of K₂CO₃ = ?
= (1.35 × 138)/1 = 186.3g
How many liters of SO2 will be produced from 26.9L O2?
Answer:
26.9 L SO₂
Explanation:
Step 1: Write the balanced equation
S(s) + O₂(g) = SO₂(g)
Step 2: Establish the appropriate volume ratio
For gases at the same conditions, the volume ratio is equal to the molar ratio. The volume ratio of O₂(g) to SO₂(g) is 1:1.
Step 3: Calculate the liters of SO₂ produced from 26.9 L of O₂
We will use the previously established volume ratio.
26.9 L O₂ × 1 L SO₂/1 L O₂ = 26.9 L SO₂
Calculate the value of Delta H for the reaction CaCO3 --> CO2 + CaO from the following enthalpy changes:
Ca + C + 3/2 O2 --> CaCO3 ΔH = -1206.9 kJ
Ca + ½ O2 --> CaO ΔH = -635.1 kJ
C + O2 -->CO2 ΔH= - 393.5 kJ
Explanation:
crescents discuss wentz eg
Answer:
2,2,1,2
2 Ca + 2 CO2 + 1 O2 → 2 CaCO3
Explanation:
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