Answer:
See explanation
Explanation:
Crystals can be made from methanol by recrystallizing the plant extract from methanol.
The methanol/water system is heated rapidly using a hot plate and the plant extract dissolves in the heating solution until a clear solution is obtained.
The solution is now cooled rapidly. The interior of the flask used for the re crystallization may even by scratched to assist the quick formation of crystals. Large crystals of plant compounds may be obtained using this method. This process should be carried out in a fume hood because of the toxicity of methanol.
The mass of all substances present before a chemical change
A. is greater the mass of all substances remaining after the change
B. is less than the mass of all substances remaining after the change
C. equals the mass of all substances remaining after the change
Answer:
C. Equals the mass of all substances remaining after the change.
Explanation:
Antoine Lavoisier's 1789 discovery in regards to the Law of Conservation of Mass states that no mass is created nor destroyed in a chemical reaction.
Min increases the temperature of a gas in an expandable container. If she keeps the pressure constant, what will happen to the volume of the gas?
Answer:
The volume will remain the same.
Explanation:
The volume of a given gas sample is directly proportional to its absolute temperature at constant pressure (Charles's law)
There are so many gas laws like Charles's law, Avogadro’s law, Boyle 's law and many more. If pressure of gas is kept constant, then volume of the gas will be increasing.
What is Charles's law?According to Charles's law, gas expands on heating. At constant pressure, volume well be directly proportional to temperature.
According to ideal gas equation
PV=nRT
On keeping pressure constant the following equation can be deduced to Charles's law as
V₁÷T₁=V₂÷T₂
where,
V₁= initial volume
V₂= final volume
T₁=initial temperature
T₂=final temperature
According to Charles's law, the volume of a given gas sample is directly proportional to its absolute temperature at constant pressure.
Therefore, if pressure is kept constant, then volume of the gas will be increasing.
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.
Another source of energy is nuclear energy. Nuclear energy is the energy in the nucleus of an atom. We can release this energy and use it to make electricity. In this project, you will research nuclear energy.
OBJECTIVES
Research nuclear energy and its use for generating electricity.
Directions
Use the library, internet, and other educational resources to research nuclear energy.
Write a three-paragraph report on what you have learned. Be sure to include the uses of nuclear power, how it is generated, and the impact it has on the environment. Also, answer the question, "Is nuclear energy renewable?"
Yes.Nuclear energy is renewable
Alkaline earth metals are elements present in the second group of the periodic table.
True or false
Answer:
True
Explanation:
Alkaline earth metals are found in the second group on the periodic table. They are made up of elements:
Beryllium
Magnesium
Calcium
Strontium
Barium
Radium
These elements have two valence electrons in their outer most shell. Together with group one elements they are s-block elements.
Group one elements are called Alkali metals. Certain periodic properties trend across the group.Photosynthesis uses all of the following except___to make food.
A) Carbon dioxide
B) Chemical energy
C) Light energy
D) Water
Answer:
A
Explanation:
thanks me hehe lovelots
What period has the highest ionization energy?
Answer:helium or the noble gases
Explanation: The ionization energy decreases from top to bottom in groups, and increases from left to right across a period. Thus, helium has the largest ionizing energy
Which of these is an example of mutualism
Answer:
B.
Explanation:
Mutualism is the idea that both organisms benefit from an interaction. In example B, the honeybee benefits because they receive nectar, while the flower benefits in being pollinated.
The map below shows the top view of a meandering stream as it enters a lake.
At which point, along the stream, are erosion and deposition?
A.
Erosion occurs at points B and D, deposition occurs at A and C
B.
Erosion occurs at points A and B, deposition occurs at C and D
C.
Erosion occurs at points A and C, deposition occurs at B and D
D.
Erosion occurs at points B and C, deposition occurs at A and D
Answer:
c
Explanation:
The erosion starts at A moving sand or soil, then drops it at B-D.
Can someone please help me ? Click the picture
Explanation:
Keq =[NO2] ^2 / [N2 O4]
4.64 x 10^-3
(04.01 LC)
Match each term to its meaning. (3 points)
Substance at the beginning of a reaction
[Choose ]
Substance at the end of a reaction
[Choose]
Number placed before a compound in a
chemical equation
[Choose ]
Answer:
Substance at the beginning of a reaction- reactant
Substance at the end of a reaction- product
Number placed before a compound in a chemical equation- stoichiometric coefficient
Explanation:
In a reaction equation, the species written on the left hand side of the equation are called the reactants.
The reactants combine to form the species on the right hand side of the reaction equation called products.
The stoichiometric coefficient is a number written before the formula of a compound in the reaction equation.
please helpp The “wall” and the spaces in between are just like the_______ in a living cell.
Answer: cell membrane
Explanation: Plzz mark me as brainliest!
what 2 elements are in the same group?
Sodium and Calcium
Fluorine and Neon
Chlorine and Bromine
Carbon and Aluminum
Answer:
Chlorine and Bromine are in the same group
Answer:
I think fluorine and neon
Would the moon phases change if the earth was rotated 90 degrees? If so, how?
Answer:
This is a very hypothetical question with a very scientifically hypothetical answer, keep in mind.
If Earth's axis tilted to 90 degrees, extreme seasons would cause intense climate change on every continent. During the summer, the Northern Hemisphere would experience nearly 24 hours of sunlight for months, which could melt ice caps, raise sea levels, and flood coastal cities.
All of the following are landforms that can contribute to climate EXCEPT
A. Volcanoes
B. Mountains and shorelines
C. Mountains
D. Iceberg
How many moles are equal to 89.23 g of calcium nitrate?
Answer:
23
Explanation:
According to the mole concept, there are 0.541 moles which are equal to 89.23 g of calcium nitrate.
What is a mole?A Mole is defined as the unit of amount of substance . Mole is the quantity which is a measure of amount of substance of how many elementary particles are present in a given amount of substance.
Mole is defined as exactly 6.022×10²³ elementary entities. The elementary entity can either be a molecule, atom or an ion depending on the type of substance in which it is present. Amount of elementary entities present in a mole is called as Avogadro's number.
Mole is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For many of the the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound which is measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.
Number of moles = mass/molar mass= 89.23/164.88=0.541 moles.
Thus, there are 0.541 moles which are equal to 89.23 g of calcium nitrate.
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How are ionic bonds and metallic bonds different from each other?
Include: what occurs with electrons in each type of bond? How/why the atoms are attracted (bonded) to each other?
Answer:
Ionic bond is bond between a metal and non metal , metallic bonding happens between positive metals ions and negative electrons in a metal
Explanation:
ionic Bond is the transfer of electrons between a metal and non metal due to strong electrostatic force of attraction between positive metal ions and negative non metal ions
in metallic bonding , there is a force of attraction between positive metal ions and the sea of electrons surrounding it
Please Help Me!!!I will mark Brainliest!!!
Answer:/
Explanation:
The columns in the periodic table are called
groups/families
O periods
O valence electrons
nucleus
How do you determine the number of neutrons in the Bohr Model
Answer: There are many ways. (Check Explanation)
Explanation: Electrons are found outside of the nucleus. Now in the middle of the nucleus there are protons in neutrons. The way to determine the number of neutrons in the Bohr Model are many ways.
Number one, if the neutrons, protons, and electrons were color coded, take away the electrons and you are left with the 2. Then find out which color corresponds to the neutron.
If it isn't color coded, then the protons and electrons should usually be marked with either + or - on it. The one without any of this and that is in the nucleus is the neutron. Last but not least, on some of the models, it can show many protons or neutrons are in the nucleus. For example the potassium bohr model. (Check image) On here, 19+ means 19 protons and 20N means 20 neutrons.
Here are the energy levels in a fantasy hypothetical hydrogen-like atom. (You cannot use the Rydberg constant, 2.18 x 10-18 J, for this problem, therefore). What is the frequency of a photon that is absorbed when an electron goes from level 2 to level 4? Energyn = 4 -2.10 x 10-19 Jn = 3 -3.20 x 10-19 Jn = 2 - 5.20 x 10-19 Jn = 1 - 9.80 x 10-19 J
Answer:
4.7 x 10^14 Hz
Explanation:
From Bohr's theory, the energy absorbed or emitted (ΔE) by an atom transiting from one energy level to another is given as;
ΔE = E4 - E2
Where;
E4 = energy corresponding to the energy level n=4
E2 = energy corresponding to the level n= 2
ΔE = (-2.10 x 10-19) - ( - 5.20 x 10-19)
ΔE =3.1 x 10-19
But
ΔE = hf
h = Plank's constant
f= frequency of photon absorbed
f = ΔE/h = 3.1 x 10-19/6.6 x 10-34
f = 4.7 x 10^14 Hz
Lithium atom of electron configuration 2,1 , it will …………. One electron to become stable ion.
lose
Gain
Share
Answer:
lose
Explanation:
as you have mentioned it has a electronic configuration as 2,1 that means it has one electrone in its last shell which is unstable. in ur mcq it has lose,gain.share
in order to be a stable atom lithium should either give away that one electron or gain 7 electrons. so as to ur question 7 electrons is out of the track so it is lose one electron
hope this helps
what is the difference between groups and periods on the periodic table.? What do they tell you?
.Answer:
Periods are horizontal rows (across) the periodic table, while groups are vertical columns (down) the table. Atomic number increases as you move down a group or across a period.
Explanation:
Please can somebody give me the correct answers.please be realigned
I will be so grateful!!
Answer: I hope this helps :
An element in Group 5 = Bismuth (Bi)
A halogen = Fluorine (F) or Astatine (At)
An alkali Metal = Lithium (L)
A metal in Group 6 = Selenium (Se) , Tellurium (Te) , Polonium (Po)
A gas made up of individual atoms = Argon (Ag)
An element that forms 1+ ions = Lithium
The most reactive element in Group 1 = francium (it doesn't appear in the image)
The most reactive element in Group 7 = Fluorine
An element that is a good catalyst= Iron (Fe) Cobalt (Co) , Nickel (Ni)
An element that does not react with anything = Argon
A metal that floats on water = Lithium
An element with a full outer energy of electrons = Helium (He), neon (Ne), and argon (Ar)
A transition Metal = Iron (Fe) Cobalt (Co) , Nickel (Ni)
A noble gas = Argon (Ar)
The element in Group 6 , Period 5 = Molybdenum , Tellurium
A non-metal = Fluorine , Argon
A gas made up of Diatomic molecule = Argon (Ar)
An element that forms 1- ions =
The Group 1 element with the highest melting point = Lithium
The Group 7 element with the highest boiling point = Astatine (As)
An element with 3 electrons in it's outer energy level = Boron
An element that forms coloured compounds = Iron
An element that has a coloured vapour = Chlorine Fluorine
A metal that can form ions with different charges = Iron, Cobalt , Lead
Explanation:
Halogen : Are any of the six nonmetallic elements that make up Group 17 of the periodic table e.g fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At).
All elements in Group 1 are Alkali metals( except hydrogen)
Examples :lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr).
A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen)
Argon is one of the inert gases that normally exist as single atoms.
Transition metals are good metal catalysts because they easily lend and take electrons from other molecules. A catalyst is a chemical substance that, does not affect the thermodynamics of a reaction but increases the rate of reaction.
Transition metals ; Scandium. Titanium. Vanadium. Chromium. Manganese. Iron. Cobalt. Nickel.
Noble gases(inert gases) don't react with anything . The family of noble gases includes helium, neon, argon, krypton, xenon, and radon.
Lithium is the lightest metal and has density about half of water.
Group 18 elements (helium, neon, and argon are shown) have a full outer, or valence, shell.
chlorine, fluorine, carbon, nitrogen, arsenic, phosphorus, selenium are examples of non-metal.
Noble gases : helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn).
The following 5 element gases are found as diatomic molecules at room temperature and pressure:
Hydrogen – H. ...
Nitrogen – N. ...
Oxygen – O. ...
Fluorine – F. ...
Chlorine – Cl.
Lithium, Li melts at 180°C.
From the lowest boiling and melting point to the highest, the group in order is fluorine, chlorine, bromine, iodine and astatine.
Like other transition metals, iron forms coloured compounds. The table shows some examples of these. Note that iron can form two different ions in its compounds. Iron(II) compounds contain the Fe 2+ ion and iron(III) compounds contain the Fe 3+ ion.
Elements in group seven(Halogens) : As you move down the group the halogens become darker in colour. For example fluorine is a very pale yellow whereas iodine will be dark purple in colour when it is in a vapour state.
A few elements, all metals, can form more than one possible charge. For example, iron atoms can form 2+ cations or 3+ cations. Cobalt is another element that can form more than one possible charged ion (2+ and 3+), while lead can form 2+ or 4+ cations.
The usage of solar, wind, and geothermal energy resources is most limited by:
(answer choices)
A.laws prohibiting the use of the resources
B.size of the resources
C.animal habitat around the resources
D.location of the resources
Can someone help me please ?
Answer:
1.w
2. Z
3. Y
4.X
...................
A student collected a sample of a gas in a 220 mL gas bulb until is pressure reached 0.757 atm at a temperature of 25.0 . The sample weighed 0.299g. What is the molAR mass of the gas?
Answer:
43.84 g/mol
Explanation:
We use the ideal gas law to find the number of moles of gas present.
So PV = nRT where P = pressure of gass = 0.757 atm, V = volume of gas = 220 mL = 0.22 L, T = temperature of gas = 25 °C = 273 + 25 = 298 K and R = molar gas constant = 0.082 L atm mol⁻¹K⁻¹.
So, n = PV/RT = 0.757 atm × 0.22 L/(0.082 L atm mol⁻¹K⁻¹ × 298 K) = 0.16654 L atm/24.436 L atm mol⁻¹ = 0.00682 mol.
Since mass of gas m = 0.299 g
and n = m/M where M = molar mass of gas
So, M = m/n
\= 0.299 g/0.00682 mol
= 43.84 g/mol
So, the molar mass of the gas is 43.84 g/mol
John is outstanding forward on his club select soccer team. He is know for his ball control and speed. After a game he often makes a sketch of moves that were successful. The dotted line on his sketch shows the direction the ball was moving before he kicked it.
Answer:
This self evaluation helps them to better his sport.
Explanation:
This is the right way to evaluate the performance of John because this sketch shows him the way he perform in the match. Due to this sketch he can better his performance and remove all the mistakes he had done in the match which results in better performance of John in the next match. This self evaluation helps them to better his sport and got new chances in order to select for a better club or national soccer team.
KBr + AgNO3 → AgBr + KNO3
Which two chemicals are products in the chemical reaction?
Answer:
Products are AgBr and KNO3
21.If the anion in an ionic compound is a nonmetal, you must change its ending
-ate
-ite
-ide
Answer:
-ite --> Anionite
Explanation:
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___________ is a characteristic of a substance that's observed during a chemical reaction. *
physical property
physical change
chemical property
chemical change