Answer: The best way to promote the process are:
--> Add a bit of solid as a seed crystal.
--> Scratch the bottom of the flask gently with a stirring rod.
Explanation:
A crystal growth is seen is SUPERSATURATED solutions which contains more solute than it can normally dissolve at that given temperature. It is usually very UNSTABLE and capable of releasing the excess solute if disturbed, either by shaking or seeding with a tiny crystals.
Crystallization can be used for the separation of two salts with different solubilities as well as for purification of a soluble salt that contains insoluble solid impurities. Recrystallization improves the validity of the process. Crystallization can be initiated by:
--> Scratching the bottom of the flask gently with a stirring rod: scratching initiates crystallization by providing energy from the high-frequency vibrations.
--> Adding a bit of solid as a seed crystal: Seed crystals create a nucleation site where crystals can begin growth.
In its aqueous solution, 32% of a substance dissociates to release hydroxide ions. Which of the following is true for the substance? (3 points)
It is a weak acid
It is a weak base.
It is a strong acid
It is a strong base.
*please only answer is you have the real answer bc I really need to bring up my grade*
Answer:
It is a weak base.
Explanation:
A base is a substance that releases hydroxide ion (OH-) when in an aqueous solution, according to Svante Arrhenius definition of a base. However, a base is said to be either strong or weak depending on it is able to dissociate.
A weak base is a base that does not completely dissociate into hydroxide ions in an aqueous solution while a strong base dissociates completely. According to this question, 32% of a basic substance ( because it can dissociate into OH-) dissociates to release hydroxide ions. This means that since it does not totally dissociate i.e. 100%, it is a WEAK BASE.
Answer:
It is a weak base.
Explanation:
Guy above me is right and I took the test :)
Why do need need pure substances
Answer:
To extract its derivatives without impurities
A 6.00 g sample of an optically pure compound was dissolved in 40.0 mL of CCl4. The observed rotation was +3.30 °, measured in a 10.0 cm (1.00 dm) polarimeter tube.
The question is incomplete, the complete question is:
If a 6.00 g sample of an optically pure compound was dissolved in 40.0 mL of [tex]CCl_4[/tex] and the observed rotation was +3.30°, measured in a 10.0 cm (1.00 dm) polarimeter tube, how would one determine the specific rotation of the pure compound?
Answer: The specific rotation of the pure compound is [tex]+22^o[/tex]
Explanation:
To calculate the specific rotation of a pure compound, we use the equation:
[tex][\alpha]=\frac{\alpha_{\text{observed}}}{C\times l\text{( in dm)}}[/tex]
where,
[tex][\alpha][/tex] = specific rotation of a pure compound
[tex]\alpha_{\text{observed}}[/tex] = observed rotation of the compound = [ex]+3.30^o[/tex]
C = concentration in g/mL = 6.00 g/40 mL = 0.15 g/mL
l = path length = 1.00 dm
Putting values in above equation, we get:
[tex][\alpha]=\frac{+3.30^o}{0.15\times 1.0}[/tex]
[tex][\alpha]=+22^o[/tex]
Hence, the specific rotation of the pure compound is [tex]+22^o[/tex]
Which statement accurately describes how electrical power and voltage are
related?
A. Power decreases as voltage increases.
B. Power is always half the amount of voltage.
C. Power is always twice the amount of voltage.
D. Power increases as voltage increases.
Answer: B
Explanation:
According to Ohm's Law, the answer is B.
Ohm's Law states that power is equal to volume x current.
If volume x current equals power, that means they are both 50% of power.
Ohm's Law:
power = voltage x current
current = voltage x power
voltage = power x current
I hope this answer helped.
Power is always half the amount of voltage. Hence, option B is correct.
What is voltage?Voltage is the potential difference between two points in a circuit or the electromotive force in a given circuit and is expressed in volts (V).
Voltage is measured by a device called a voltmeter that is always connected in parallel with the current source.
When voltage is measured between two points on a wire in a circuit with zero or no resistance in between the two points then the voltage will be zero.
From the ohm's Law, voltage is given the product of resistance and current and thus if the resistance is zero then the voltage will be zero.
Ohm's Law states that power is equal to volume x current.
If volume x current equals power, that means they are both 50% of power.
Ohm's Law:
power = voltage x current
current = voltage x power
voltage = power x current
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the correct sequence where reactivity towards oxygen increases.
Answer:
Option D is good to go!
Explanation: as per the reactivity series more reactive substances will react with the counterpart substance.The most reactive substance here is calcium while the least reactive is aluminium, the magnesium comes in between.As per their reactivity, these substances will react with oxygen.
Explanation:
PLEASE HELP!!!
What are the products of a hydrogen fusion reaction?
A. Deuterium
B. Carbon-14
C. Plutonium and a neutron
D. Helium and a neutron
Answer:
b
Explanation:
Deuterium is the products of a hydrogen fusion reaction, the correct option is A.
What is hydrogen fusion?It is the situation in which two hydrogen atoms merge or coalesce to form a helium atom.
A portion of the hydrogen's mass is transformed into energy during the process.
The fusion reaction that abilities the Sun and stars occurs when hydrogen atoms merge to produce deuterium, and then deuterium and hydrogen atoms fuse to form helium, releasing energy.
Four Hydrogen nuclei (protons) combine to form a Helium nucleus in the basic Hydrogen fusion cycle.
Actually, electrons, neutrinos, and photons are involved in the hydrogen fusion into helium.
Since the total mass of the eventually results single nucleus is lower than the mass of the original two nuclei, the process releases energy.
Thus, the correct option for the given case is A.
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2 NH3 + 3 CuO --> 3 Cu + N2 + 3 H2O
In the above equation, how many moles of N2 can be made when 113.6 grams of CuO are consumed?
Round your answer to the nearest tenth. If your answer is a whole number like 4, report the answer as 4.0
Use the following molar masses. If you do not use these masses, the computer will mark your answer incorrect. :
Element Molar Mass
Hydrogen
1
Nitrogen
14
Copper
63.5
Oxygen
16
Answer: 0.5 moles of [tex]N_2[/tex] are produced in the reaction
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 mass of [tex]CuO[/tex] = 113.6 g
Molar mass of [tex]CuO[/tex] = 79.5 g/mol
Plugging values in equation 1:
[tex]\text{Moles of CuO}=\frac{113.6g}{79.5g/mol}=1.43 mol[/tex]
For the given chemical reaction:
[tex]2NH_3+3CuO\rightarrow 3Cu+N_2+3H_2O[/tex]
By the stoichiometry of the reaction:
If 3 moles of [tex]CuO[/tex] produces 1 mole of [tex]N_2[/tex]
So, 1.43 moles of [tex]CuO[/tex] will produce = [tex]\frac{1}{3}\times 1.43=0.476=0.5mol[/tex] of [tex]N_2[/tex]
Hence, 0.5 moles of [tex]N_2[/tex] are produced in the reaction
Need help for this answer
Answer:
animals that live in the desert hibernate in winter
am not sure
how many moles are in 3.25188x10^24 molecules of CO2
Answer: C is right
Explanation: One mole is 6.022 x 10^23 molecules.
Dividing 3.25188 x 10^24 / 6.022 x 10^23 = 5.4 moles
potential (P) energy or kinetic (K) energy
Runners “on their marks” at the start line of a race _____
If a speaker is moved from 2 feet away to 4 feet away, the volume of the sound will: half double quarter stay the same
Answer:
the volume of the sound will quarter
Explanation:
As you move far away from the source, the loudness of sound decreases. This is because as the distance from the source increases, the area it covers also increases thereby spreading the energy over a great area leading to lesser loudness and intensity.
As a result of this, sound intensity follows an inverse square law:
I ∝ 1/d²; where I is the intensity and d is the distance from source.
Therefore If a speaker is moved from 2 feet away to 4 feet away (increment of 2 feet), the volume of the sound would quarter (1/2² = 1/4)
Which of the following molecules or ions has a bent shape?
A: CIO4
B: PH3
C: OF2
D: PCI5
A. The sequence of bases in one DNA strand is given below. Identify the complementary sequence of bases
in the other strand of DNA.
1.
А A
с
T
С
T
G
C
с
А
T
Answer:
The complementary sequence of bases in the complementary strand of the given single DNA strand AACTCTGCCAT will be:
TTGAGACGGTA
Explanation:
The primary structure of DNA is a double-stranded helix of nucleotides linked to each other by phosphodiester linkages. The two strands of the DNA molecule is complementary to each other. While one strand is linked in the 3' to 5' direction, the other strand is linked in the 5' to 3' direction. The two strands are held together by hydrogen bonds between the nucleotides of the two strands and this is known as base pairing. In base pairing, adenine nucleotide, A, on one strand forms two hydrogen bonds with thymine nucleotdie, T, in the other strand. Also, guanine nucleotide, G, in one strand, forms three hydrogen bonds with cytidine nucleotide, C, in the complementary strand.
Therefore, once the nucleotide sequence of one DNA strand is known, the nucleotide sequence of the complementary strand can easily be deduced.
The complementary sequence of bases in the complementary strand of the given single DNA strand AACTCTGCCAT will be: TTGAGACGGTA
PLEASE SOMEONE! The density of the acetic acid solution is 1.05 g/mL. Calculate the %(m/m) of the acetic acid solution (convert mol/L to %(m/m)).
CH3COOH(aq) + NaOH(aq) = CH3COOHNa(aq) + H2O(L)
Volume of CH3COOH = 0.1L
Titration Equation: CH3COOH(aq) + NaOH(aq) = CH3COOHNa(aq) + H2O(L)
Concentration of CH3COOH = 0.243 mol/L
Answer:
The Percentage concentration of acetic acid = 1.39 %
Explanation:
Density of acetic acid solution = 1.05 g/mL
Volume of acetic acid solution = 0.1 L = 100 mL
From the formula, Density = mass / volume; mass = density × volume
Mass of acetic acid solution = 1.05 g/mL × 100 mL = 105 g
Molar concentration of acetic acid solution = 0.243 mol/L
Molar mass of acetic acid, CH₃COOH = (12 × 2 + 1 ×4 + 16 ×2) = 60 g/mol
From the formula, mass concentration = molar concentration × molar mass
Mass concentration of acetic acid, CH₃COOH = 0.243 mol/L × 60 g/mol = 14.58 g/L
In one liter of acetic acid solution, there are 14.58 g of acetic acid. Therefore, in 0.1 L, there will be 14.58 × 0.1 = 1.458 g of acetic acid.
Percentage concentration of acetic acid = mass of acetic acid / mass of acetic acid solution × 100%
Percentage concentration of acetic acid = (1.458 / 105) × 100% = 1.39 %
The Percentage concentration of acetic acid = 1.39 %
Which electron in an atom (Z=17) is the most shielded from
nuclear charge?
A. an electron in the 2s
B. an electron in the 3p
C. an electron in the 3d
D. an electron in the 1s
Answer:
option no. C is correct
an electron in the 3d
Comparing the sizes of these atoms, which atom is smallest?
a.rubidium
b.zirconium
c.lead
d.silver
e.xenon
Answer:
xenon
Explanation:
Rb>Zr>Ag>Pb>Xe
4Fe (s) + 3 O2 (g) → 2 Fe2O3 (s)
A. What is the oxidation number for each item in this equation?
B. What is being oxidized?
C. What is being reduced?
D. What is the oxidizing agent?
E. What is the reducing agent?
Explanation:
The number acquired by an element after the lose or gain of an electron is called oxidation number.
For example, [tex]4Fe(s) + 3O_{2}(g) \rightarrow 2Fe_{2}O_{3}(s)[/tex]
Here, oxidation number of Fe(s) is 0 and Fe in [tex]Fe_{2}O_{3}[/tex] is +3.
Oxidation number of O in [tex]O_{2}(g)[/tex] is 0 as it is present in its elemental state.
The oxidation number of O in [tex]Fe_{2}O_{3}[/tex] is calculated as follows.
[tex]2(3) + 3x = 0\\6 + 3x = 0\\x = \frac{-6}{3}\\= -2[/tex]
Hence, oxidation number of O in [tex]Fe_{2}O_{3}[/tex] is -2.
The loss of electrons by an element or substance is called oxidation. Here, electrons are being lost by Fe(s) as an increase in oxidation state is occurring. So, Fe(s) is oxidized.The gain of electrons by an element or substance is called reduction. Here, electrons are being added to [tex]O_{2}[/tex] as a decrease in its oxidation state is occurring. So, [tex]O_{2}[/tex] is reduced.An element or compound which is being reduced is called oxidizing agent. Here, [tex]O_{2}[/tex] is the oxidizing agent.An element or compound which is being oxidized is called reducing agent. Here, Fe(s) is the reducing agent.What is the molecular formula of the compound CH2 with molar mass = 42.0 g/mol? A. C2H18 B. C2H4 C. CAHg O D. C3H6
The molecular formula of the compound CH2 with molar mass = 42.0 g/mol is C₃H₆. Therefore, option D is correct.
What is molar mass ?The term molar mass is defined as the mass in grams of one mole of a substance. The units of molar mass are grams per mole, abbreviated as g/mol.
First, let's find the molar mass of CH₂.
The molar mass CH₂= 12.0 + (2 x 1.01)
= 14.02 g/mol
Now to determine the molecular formula, we need to find the ratio based in the molar masses.
42 / 14.02
= 2.99
≅ 3
Therefore, the ratio is 3, the molecular formula is C₃H₆.
Thus, option D is correct.
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A water pipe bursting in the winter is a result of which type of weathering?
A. Biological
B. Freeze-thaw
C. Exfoliation
D. Chemical
Answer:
Freeze-thaw
Explanation:
Water expands slightly when it freezes to form ice. This is why water pipes sometimes burst in the winter. You might have seen a demonstration of this sort of thing - a jar filled to the brim with water eventually shatters after it is put into a freezer. The formation of ice can also break rocks.
A set of charged plates is
separated by 8.08*10^-5 m. When
2.24*10^-9 C of charge is placed
on the plates, it creates a potential
difference of 855 V. What is the
area of the plates?
(The answer is _*10^-5 m^2. Just fill
in the number, not the power.)
Answer:
2.39×10¯⁵ m²
Explanation:
From the question given above, the following data were obtained:
Distance (d) = 8.08×10¯⁵ m
Charge (q) = 2.24×10¯⁹ C
Potential difference = 855 V
Area(A) =?
NOTE: Permittivity (ε₀) = 8.854×10¯¹² F/m
The area can be obtained as follow:
q = ε₀AV/d
2.24×10¯⁹ = 8.854×10¯¹² × A × 855 / 8.08×10¯⁵
2.24×10¯⁹ = 7.57×10¯⁹ × A / 8.08×10¯⁵
Cross multiply
7.75×10¯⁹ × A = 2.24×10¯⁹ × 8.08×10¯⁵
7.75×10¯⁹ × A = 1.81×10¯¹³
Divide both side by 7.75×10¯⁹
A = 1.81×10¯¹³ / 7.75×10¯⁹
A = 2.39×10¯⁵ m²
Thus, the area of the plate is 2.34×10¯⁵ m²
Answer:
2.39
Explanation:
Use the activity series below to predict whether the following reactions will take place.
Answer:
first one is yes, second one is no
Explanation:
edge
Use the table to compare the solubility of substances. Check all of the boxes that apply.
Aspirin is less soluble than table salt, but more soluble than carbon dioxide.
A salt water solution can be made by dissolving 20 g NaCl in 50 mL water.
A saturated solution of table sugar is more concentrated than a saturated solution of table salt.
Increasing the temperature will increase the solubility of all the solutes in the table
**Check for proof photos at the bottom.**
_____________________________________Use the table to compare the solubilities of substances. Check all of the boxes that apply.
A. Aspirin is less soluble than table salt, but more soluble than carbon dioxide.
C. A saturated solution of table sugar is more concentrated than a saturated solution of table salt.
_____________________________________The solubility of glucose at 30°C is 125 g/100 g water. Classify a solution made by adding 550 g of glucose to 400 mL of water at 30°C. Explain your classification, and describe how you could increase the amount of glucose in the solution without adding more glucose.
Answer: The solution is saturated. At 30°C, 500 g of glucose will dissolve in 400 mL of solution. Of the 550 g glucose added, only 500 g will dissolve and 50 g will precipitate out. The amount of glucose in the solution can be increased by heating the solution because the solubility of solids tends to increase with temperature.
_____________________________________Use the graph to identify the number, letter, or word that completes each statement.
• The solubility of Solute D decreases as temperature increases.
• The solubility of Solute E increases the most as temperature increases.
• The solubility of Solutes C and D is the same at 20°C.
• As the temperature increases from 0 to 100, the solubility only changes by about 5 grams for Solute B.
_____________________________________Explanation:In the provided table shows the solubility of 4 different substances. The solubility number for Aspirin is smaller than the number for table salt, but larger than the number for carbon dioxide. Since the solubility if sugar is larger than table salt, its saturated concentration would be higher.
In the given chart, the line representing solubility of solute D decreases as temperature increases. The line for solute E increases the most. At 20°C, the lines of C and D are about the same height.
Here are photos of Edge just incase.
Answer:
A & C
Explanation:
What is the standard reduction potential, e, for the half-reaction Zn2+(aq) +2e → Zn(s)?
A. -0.76 V
B. -1.68 V
C. -2.37 v
D. -2.71 V
The standard reduction potential for the half-reaction Zn²⁺(aq) + ⁻2e → Zn(s) is -0.76 V; option A
What is standard reduction potential?
The standard reduction potential of a chemical species is the a measure of the potential of a given chemical species to be reduced rather than being oxidized.
This measurement is done under standard conditions of concentration, pressure and temperature.
The standard reduction potential for the half-reaction Zn²⁺(aq) + ⁻2e → Zn(s) is -0.76 V.
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Explain how monumentum conservation is applied in ball games
Answer:
Hi , your answer is that At impact, the cue ball stops, but transfers all of its momentum and kinetic energy to the other ball, resulting in the hit ball rolling with the initial speed of the cue ball. In an inelastic collision, momentum is conserved, but the total kinetic energy of the system is not conserved
Explanation:
i really hope i helped , pleae give me brainliest , have a nice day and thank you in advance :) .
When naming a molecule, how do you indicate that the carbons on either side
of the double bond are pointing in opposite directions?
Answer:
use the prefix trans-
When naming a molecule, we indicate that the carbons on either side of the double bond are pointing in opposite directions by adding a prefix (-trans) in the name of the molecule.
What is IUPAC nomenclature?IUPAC nomenclature of organic compounds refers to the systematic approach taken for the nomenclature of organic compounds as per the recommendation of the International Union of Pure and Applied Chemistry.
If alkenes have two different substituents at each end of the C=C then they can exist as stereoisomers (as geometric isomers).
This is because there is restricted rotation of the double bond due to the pi bond which means they don't readily interconvert.
cis- if the two alkyl groups, R-, are on the same side of the C=Ctrans- if the two alkyl groups, R-, are on opposite sides of the C=C.Therefore, When naming a molecule, we indicate that the carbons on either side of the double bond are pointing in opposite directions by adding a prefix (-trans) in the name of the molecule.
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How many moles of aluminum oxide are produced when 6 moles of oxygen gas react?
4Al + 3O2 → 2Al2O3
Answer:
4 moles of aluminum and 6 moles of oxygen are produced
Which mathematical statement shows the formula for weight?
Answer
(:
Weight is basically a measure of theme force of gravity pulling down on an object. It depends on the object's mass and the acceleration due to gravity, which is 9.8 m/s2 on Earth. The formula for calculating weight is F = m × 9.8 m/s2, where F is the object's weight in Newtons (N) and m is the object's mass in kilograms.
Explanation:
Please somone help me with a chemistry question brainliest to whoever answers correctly and 20 points
Answer:
chlorine is larger so the symbol is <
Explanation:
Given the balanced equation representing a reaction:
HCl + H2O H3O+ + Cl-
The water molecule acts as a base because it
Answer:
It accepted a proton from HCl
Explanation:
When properly written, the equation box the reaction is given as; HCl(aq) + H2O(l) ----> H3O+(aq) + Cl-(aq).
According to Brownstead-Lowry definition of acids and bases, an acid donates protons while a base accepts protons.
Water molecule acts as a base in the reaction because it accepted a proton from HCl in the reaction above.
How much work (in J) is involved in a chemical reaction if the volume decreases from 5.20 to 1.13 L against a constant pressure of 0.852 atm ? Express your answer to three significant figures and include the appropriate units.
Answer:
W = 350.6 J
Explanation:
Given that,
The volume decreases from 5.20 to 1.13 L against a constant pressure of 0.852 atm.
The change in volume = 1.13 L - 5.20 L = -4.07 L
Work done, W = - PΔV
So,
W = 0.852 atm × -4.07 L
= - 3.46 L-atm
or
[tex]W=3.46\ L-atm\times \dfrac{101.33\ J}{1\ L-atm}\\\\=350.6\ J[/tex]
So, the required work done is 350.6 J.