Answer:
Dissolves a chemical sample well at high temperatures.
Does not dissolve a chemical sample well at low temperatures.
Explanation:
Recrystallization is a purification technique that involves mixing of an impure solid compound with a hot solvent leading to a saturated solution. As this solution cools, the compound to be purified becomes less soluble in the solvent, and pure crystals appear from the solution as the solution cools.
A good recrystallization solvent should
Not dissolve the compound that we want to purify at room temperature Dissolve the compound completely only at the solvent's boiling point Dissolve all the soluble impurities in the sample very well at room temperature.Have a fairly low boiling point such that its boiling point is lower than the melting point of the compound to be purified and evaporates easily when air-drying the sample.Why can you see solids and liquids, but not most gases?
Why can gases and liquids be paired but not solids?
The atoms and molecules in gases are much more spread out than in solids or liquids. They vibrate and move freely at high speeds. A gas will fill any container, but if the container is not sealed, the gas will escape. Gas can be compressed much more easily than a liquid or solid.
Using the two cell reduction potentials shown for their corresponding reaction, calculate the cell potential for a voltaic cell made from these two systems.
Question 17 options:
A)
1.68 V
B)
–0.78 V
C)
0.78 V
D)
–1.68 V
Answer:
Theory- 1 to 7
Explanation:
Exercise- 8 to 25
ect
The right alternative is Option D (0.78 V).
According to the question,
By putting the values, we get
Cu+2 + 2e → Cu E = 0.52 V
Ag+1 + 1e Ag E° = 0.78 V
= 1.23 - 0.45
= 0.78.
Is cell potential negative or positive?negative
The standard cell potential is quite negative, so the reaction will not occur spontaneously as written.
Missing parts of the question.
Using the two cell reduction potentials shown for their corresponding reaction, calculate the cell potential for a voltaic cell made from these two systems: 0.78.
Cu+2 + 2e → Cu E = 0.52 V
Ag+1 + 1e Ag E° = 0.80 V
options:
A)
0.28 V
B)
–1.32 V
C)
1.32 V
D)
–0.28 V
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Hydrogen bromide is a chemical compound. It’s formed from atoms of hydrogen and bromide, two
A
electrons.
B
elements.
C
neutrons.
D
nuclei.
Answer: The correct option is B. elements.
Explanation:
A chemical compound is defined as the specie which is formed by the combination of two or more elements. For example: Water, carbon dioxide, etc..
Elements is defined as the chemical specie which consists of only one type of atom. For example: Hydrogen, Oxygen, etc..
Now, when hydrogen element and bromine element combines, it leads to the formation of a heteronuclear chemical compound known as hydrogen bromide having chemical formula HBr.
Hence, the correct option is B. elements.
Hydrogen and bromine are two elements that form hydrogen bromide (HBr).
COMPOUND:
A compound is a chemical substance made up of chemical combination of two or more elements. According to this question, Hydrogen bromide is a chemical compound formed from atoms of hydrogen (H) and bromine (Br). These two atoms that make up hydrogen bromide are that of elements. Therefore, it can be said that hydrogen and bromine are two elements that form hydrogen bromide (HBr).Learn more at: https://brainly.com/question/13516179?referrer=searchResults
Write ashort note on the
first battle of
of panipat
Answer:
The First Battle of Panipat was fought between the invading forces of Babur and the Lodi Empire, which took place on 21 April 1526 in North India. It marked the beginning of the Mughal Empire. This was one of the earliest battles involving gunpowderfirearms and field artillery.
For you to write an essay on Panipat first bring into view
Introduction body conclusionThen write a brief story using this format.
How to write a short note on the first battle of Panipat?In writing this essay, you must consider the structure and content of the essay or short note
For structure kick off with
Introduction body conclusionIn conclusion, for the content of the short note you can consider this,
Panipat fought its first battle on 21 April 1526 in the North of India, This battle was fought between the invading powers of Babur and the Lodi Empire.
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Which lists important roles of coral reefs?
cleaning oil from oceans, protecting beaches, producing oxygen
producing oxygen, offering medical benefits to humans, supporting a variety of organisms
supporting a variety of organisms, cleaning oil from oceans, producing oxygen
offering medical benefits to humans, protecting beaches, supporting a variety of organisms
Answer:
D. offering medical benefits to humans, protecting beaches, supporting a variety of organisms
Explanation:
I took the test and put C and got it wrong and l went back to see what the correct answer as and it was D.
A 600. mL beaker has an inner diameter of 77.0 mm. What is the vertical distance between the 100. mL marks on the side of the beaker
Answer:
[tex]h=12.9cm[/tex]
Explanation:
Hello!
In this case, since we can consider the beaker until the 100-mL mark as a cylinder, we can use the following equation to relate its diameter, vertical distance or height and volume:
[tex]V=\pi h\frac{d^2}{4}[/tex]
Thus, since we know the diameter, volume (which is equivalent to 600 cm³) and π, we can plug in to obtain:
[tex]600cm^3=\pi *h*\frac{(77.0mm)^2}{4}[/tex]
It means it is necessary to take the mm to cm and solve for h:
[tex]h=\frac{600cm^3}{\pi*\frac{(7.70cm)^2}{4}} \\\\h=12.9cm[/tex]
Best regards!
The distance between each 100 mL mark is 2.15 cm.
The volume of a cylinder is obtained using the formula;
V = πr^2h
Now, we have the following information;
Volume of the cylinder = 600. mL or 600 cm^3
Diameter of the cylinder = 77 mm or 7.7 cm
Radius of the cylinder = 7.7/2 = 3.85 cm
Height of the cylinder = h
Hence;
600 = 3.142 × ( 3.85 )^2 × h
h = 600/3.142 × ( 3.85 )^2
h = 12.88 cm
There are six 100 mL marks on the beaker, the distance between each 100 mL mark = 12.88 cm/6 = 2.15 cm
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How many moles of NaHCO3 are there in a 3g tablet of Alka-Selzer?
Tell me this why don't water stop my mouth from burning but milk or malk does this s for 32 points
Answer:
water spreads the spicy taste around your mouth, while milk does not and it helps the hot taste go away.
Explanation:
Answer:
water makes ur mouth burn more but milk it helps bc of what's in it
What is the definition of climate?
1) An area's long term weather pattern
2)When large air masses of different density, moisture, and temperature mee
3)The state of the atmosphere at a given place and time
4)Large volume of air that has similar characteristics of temperature and water
vapor content
Answer:
1) An area's long term weather pattern
Explanation:
Climate is defined as the weather pattern in an area for the long term. Climate means the usual condition of the humidity, temperature, wind, rainfall, and atmospheric pressure in the surface area of Earth for the long term. Usually the time period for a climate in a region is taken over 30-years.
Weather is the state of the atmosphere and climate the long-term weather pattern of the area. For example: degree to which it is hot or cold is weather and expect snow in the Northeast in every January is climate.
Hence, the correct answer is "1) An area's long term weather pattern".
How many protons, neutrons, and electrons does Sr^2+
Answer:
36 electrons
Explanation:
The # of protons is always equal to the atomic number. In the case of Sr (Strontium), it is 38 protons.
The 2+ at the end means that it has a charge of +2, meaning that it LOST two electrons to become a cation with a full valence shell. So, 38 - 2 = 36 electrons
Answer:
38 protons 36 electrons 30 neutron because of 29 isotope
Investigate: Press Reset. Start with 2.000 moles of sulfur, then press Start. How many atoms do you think this amount represents
Answer:
1.204428 * 10^24 atoms
Explanation:
Number of moles = 2 mol
Number of atoms = ?
The relationship between moles and atoms is given by the avogadro's umber. This is the number of units in one mole of a substance. The units can be atoms, ions etc In this case it is atoms. The number is equal to 6.02214076 * 10^23
This means;
1 mol = 6.02214076 * 10^23
2 mol = x
Upon solving for x,
x = 2 * 6.02214076 * 10^23
x = 12.04428 * 10^23
x = 1.204428 * 10^24 atoms
A family requires 20,000 KJ of fuel energy every day. If calorific vlaue
of the fuel used by them is 15,000 kJ/kg, how much of this fuel will be
required by this family to meet their energy needs for the month of April?
Answer:
40 kilograms of fuel are required to meet their energy needs for the month of April.
Explanation:
The month of April has 30 days and the full energy needed by the family is determine by the following combustion formula, derived from dimension analysis:
[tex]n\cdot Q = m\cdot L_{c}[/tex] (1)
Where:
[tex]m[/tex] - Mass of the fuel, measured in kilograms.
[tex]L_{c}[/tex] - Calorific value of the fuel, measured in kilojoules per kilogram.
[tex]Q[/tex] - Daily fuel energy, measured in kilojoules.
[tex]n[/tex] - Number of days of the month, dimensionless.
If we know that [tex]Q = 20000\,kJ[/tex], [tex]n = 30[/tex] and [tex]L_{c} = 15000\,\frac{kJ}{kg}[/tex], then the amount of fuel required to meet their energy needs for the month of April is:
[tex]m = \frac{n\cdot Q}{L_{c}}[/tex]
[tex]m = \frac{(30)\cdot (20000\,kJ)}{15000\,\frac{kJ}{kg} }[/tex]
[tex]m = 40\,kg[/tex]
40 kilograms of fuel are required to meet their energy needs for the month of April.
How many moles in 206.91 g Na
Answer:
The answer is 9.000090040048176
HELP me plzzzzzzzzzzzzzzzzz
Answer:
Explanation:
bblblblbllbllbllb1234w
CAN SOMEBODY HELP ME WITH THIS QUESTION PLEASE !! ?
hope it helps you......
Give the IUPAC name for each compound.
Answer:
a. 1-fluoro-3,3,4-trimethyl-pentane.
b. 1-iodo-3-ethyl-2-methyl-hexane.
c. 1,3-dichloro-5-dimethyl-hexane.
d. 1-bromo-3-methyl-cyclopentane.
Explanation:
Hello!
In this case, according to the IUPAC rules for the listed alkyl halides, we first need to name the halogens (considering periodic order) then alkyl radicals and finally the parent chain; thus, the names are given below:
a. 1-fluoro-3,3,4-trimethyl-pentane.
b. 1-iodo-3-ethyl-2-methyl-hexane.
c. 1,3-dichloro-5-dimethyl-hexane.
d. 1-bromo-3-methyl-cyclopentane.
e. 5-chloro-1-bromo-1,1,5-trimethyl-pentane (radicals are not clear).
Best regards!
which is a characteristics of all ions
Answer:
All ions must a overall charge
Explanation:
Answer:
i belive its B
Explanation:
How many grams of H2O are in 34.53 moles of H2O??
Answer:
m=621.54g
Explanation:
number of moles= mass of H2O/molar mass of H2O
n=m/mm
make mass the subject of the formula
m=n*mm
find molar mass of water
H2O=1(16)+2(1)
mm= 18.0g/mol. n=34.53mol
hence, m=34.53mol*18.0g/mol
m=621.54g
Which correctly lists three characteristics that are used to describe air?
O Altitude, density, radiation
O Density, radiation, mass
O mass, pressure, density
O pressure, altitude, radiation
Answer:
Mass Pressure and density.
Explanation:
Ti(SO4)2 chemical compound?
Answer:
Titanium(IV) Sulfide
Explanation:
Give an example of chemical reaction that occurs in everyday life
Answer: metal and salt water
Explanation: salt starts to brake down metal and metal is everywhere in the ocean hope this helps
Answer:
baking a cake.
Explanation:
baking a cake is an example of a chemical reaction that happens daily because a new substance is forming when the cake is being baked. hope this helps! :)
What is Darwin's name for species that do not appear to have changed for millions of years?
Since, the options have not been given the question is incomplete.
What is Darwin's name for species that do not appear to have changed for millions of years?
a.
Dinosaurs
b.
Living fossils
c.
Old souls
d.
Ancient moderns
Answer: b. Living fossil
Explanation:
In 1859 Charles Darwin proposed the term living fossil, that means a species or group of species that had not changed in terms of evolutionary context thus can be useful in tracing the extinct or previously existing forms of life. The examples of the living fossils are horseshoe crabs, ginkgo (Conifers) and tuatara. These group of animals were existed unchanged in the Ordovician, Permian, and Triassic periods respectively with few surviving species.
Answer:
the answer is living fossils so it would be b
Explanation:
how do i know i took the test
What should a student do to set a goal? Check all that apply.
Create a plan.
Make a schedule.
Schedule lots of tasks.
Rush into the goal.
Pace him or herself.
Answer:
create a plan
the ways of of a student to set a goal
1. Write clear and measurable goals
2.Create a specific plan for each goal
3.Read your goals daily and visualize yourself accomplishing them
4. Reflect yourself to see if you are on target
5. Revise your action plans if needed.
1.)make a plan
2.)make a schedule
5.)pace him or herself
2.92 x 10^-15/
(5.6 x 10^-3) (4.16 x 10^9)
Answer:
3645.46
Explanation:
calculated
How can you identify a redox reaction?
O A. The number of protons has changed in an atom.
O B. Electrons have transferred from one atom to another.
O C. The charges on each side of the equation cancel.
O D. Metal atoms have rearranged in the compounds.
SUBMIT
PREVIOUS
Answer: The Correct Answer is Choice B.
Explanation: I just took the quiz.
ANSWER:
B. Electrons have transferred from one atom to another.
EXPLANATION:
An oxidation-reduction (redox) reaction is a reaction which involves the change in oxidation number of the atoms involved. Since the oxidation number changes, this means that one atom has to lose electrons and another has to accept electrons. The reactant that loses electrons is called REDUCING AGENT while the reactant that gains electrons is called OXIDIZING AGENT.
For example, in a reaction between iron and oxygen as follows:
4Fe+ 3O2→2Fe2O3
Iron is reduced from +2 to 0 because it accepts electrons from oxygen while oxygen is oxidized from -2 to 0 because it transfers electrons to iron.
Hence, a redox reaction can be identified by the transfer of electrons from one atom to another.
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Which of the following is NOT a heterogenous mixture:
Salad
Beef Stew
Cereal in milk
Vinegar
Answer:Vinegar
Explanation:
The smallest unit of an element, which cannot be broken by any chemical means is called?
atom
compound
element unit
molecule
Decide which element probably forms a compound with hydrogen that has a chemical formula most and least similar to the chemical formula of the compound formed by hydrogen and sulfur.
Answer:
Most similar- oxygen
Least similar- sodium
Explanation:
The complete question is shown in the image attached.
Now let us consider all the options in the questions carefully. We do know that hydrogen forms covalent bonds with sulphur. Two hydrogen atoms form form two polar covalent bonds with one sulphur atom. The molecule is bent owing to the presence of two lone pairs of electrons on the sulphur central atom.
Oxygen is in the same group as sulphur in the periodic table. The compound between hydrogen and sulphur is strikingly similar to the compound formed between sulphur and hydrogen due to chemical similarity of compounds of elements in the same group of the periodic table. Hence H2O bears the greatest similarity to H2S.
The bond between hydrogen and halogens is also polar covalent but less similar to the bond between sulphur and hydrogen.
Lastly, the bond between hydrogen and sodium is ionic and least similar to the bond between hydrogen and sulpur. We actually have in that compound, Na^+ H^-. Sodium transfers one electron to hydrogen as is implied in the ionic formula shown.
Hence the answer above.
What is one way in which sound and light are alike? PLEASE HELP IF YOU WANT BRAINLEIST AND TO HAVE YOUR COMMENT LIKED!!
A. They both travel easily through wood.
B. They are both types of energy.
C. both can travel through outer space.
D. They both make it easier for you to see what you are doing.
Answer:
They are both types of energy.
Explanation:
The last 2 are true for light, and the first one is true for sound.
Hope this is right, sorry if it is not.
30 POINTS HELP Which idea was supported by Aristarchus, Copernicus, and Galileo?
The planets have epicycles.
The planets revolve around the Sun.
The stars rotate around the Sun.
The center of the solar system is Earth.
Answer:
SO SORRY it took so long but the answer is B :)
Explanation:
Trust me and good luck :)
The theory that the planets move around the sun was endorsed by Aristarchus, Copernicus, as well as Galileo. The solar system revolves around the sun.
What is Aristarchus?Aristarchus of Samos was just a Greek astronomer that suggested the very first heliocentric model of the cosmos, wherein the sun, rather than the earth, was even at its center. Despite the fact that his hypothesis was acknowledged by other philosophers of the time, it was dismissed as unrealistic, and the geocentric model remained in use for the next 1,700 years.
What is Copernicus?Copernicus was also the first to assert that the Earth as well as the other planets orbit the sun. It was really a significant shift in thinking.
What is sun?Sun can be considered as a star in solar system.
The theory that the planets move around the sun was endorsed by Aristarchus, Copernicus, as well as Galileo. The solar system revolves around the sun.
Therefore, the correct answer will be option (b).
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