Which is the electron configuration for lithium?
1s2
2s3
1s22s1
1s12s2
Answer:
1s2, 2s1
Explanation:
Lithium is the first element in the 2nd row of elements meaning its 1s orbital is completely filled and 1 electron is in the 2s orbital.
Answer:
the answer is C
Explanation:
Sugar is made up of clear, colorless crystals that dissolve easily in water, but the crystals and their solution do not conduct electricity. Which statement describes sugar? It is made up of atoms that are held together by metallic bonds. It is made up of atoms that are held together by covalent bonds. It is made up of atoms that are held together by weak ionic bonds. It is made up of atoms that are held together by strong ionic bonds.
Answer:
it is made up of atoms that are held together by covalent bond
What is the mass percent of a sodium fluoride solution prepared by dissolving 0.64 moles of sodium fluoride into 63.5 grams of water?
The mass percent of a sodium fluoride solution prepared by dissolving 0.64 moles of sodium fluoride into 63.5 grams of water is 29.7%.
What is mass percent ?Mass percent is a means to describe a component in a specific combination or to convey a concentration. The mass percentage used to describe the solution composition indicates the mass of solute contained in a given mass of solution.
To determine the mass percent of an element in a compound, we divide the mass of the element in one mole of the compound by the compound's molar mass and multiply the result by 100.
Given:
Number of moles = 0.64 moles
Moles of sodium fluoride = Given mass/molar mass
0.64 moles = Mass / 42
Mass = 26.88gram
Mass % = Mass of solute/ mass of solution × 100
= 26.88/90.48 × 100
= 29.7 %
Thus, 29.7 % is the mass percent of a sodium fluoride solution prepared by dissolving 0.64 moles of sodium fluoride into 63.5 grams of water
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If 56 grams of carbon monoxide burns in oxygen to produce 88 grams of carbon dioxide, the mass of oxygen involved in the reaction is
grams.
The answer is 32 grams!
hope I helped
During an experiment the students prepared three mixtures A)Starch in water B) Sodium chloride solution C) Tincture of Iodine. i) Students observed a visible beam of light through mixture A. Why? ii) Tincture of Iodine did not show Tyndall effect . Explain reason. iii) How can you relate particle size to Tyndall effect?
The question requires a good knowledge of the meaning of Tyndall effect or scattering of light by false solutions in chemistry
The student observed a beam of visible light through mixture A because A exhibits Tyndall effect
Tincture of Iodine does not show Tyndall effect because its solution consists of particles less than 1 nanometer in solution.
A solution may be classified as a true solution or a false solution. A true solution consists of particles which are less than 1 nanometer in solution. A true solution does not scatter visible light.
A false solution, on the other hand consists of particles larger than 1 nanometer and does scatter visible light.
Starch in water is an example of a false solution or colloid hence it exhibits Tyndall effect. The scattering of visible light by a solution is known as Tyndall effect.
Tincture of iodine and sodium chloride in water are all true solutions hence they do not scatter visible light.
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A sample of gas has a volume of 20 cm³.The pressure is changed to 90 kPa at constant temperature,while the volume increases to 75 cm³.What was the original pressure of the gas?
Answer:
337.5kPa ~ 338kPa
Explanation:
Using the ideal gas law PV=nRT we have the following definitions from the problem:
V(initial) = 20cm³
P(initial) = ?kPa
V(final) = 75cm³
P(final) = 90kPa
Since we know that the number of moles of the sample did not change, nor did the temperature, nor does the ideal gas constant (R) we can rewrite this equation to state:
P(initial)V(initial) = nRT =P(final)V(final) ~ P(initial)V(initial) = P(final)V(final)
Rearranging this equation as we are solving for the initial pressure we find that:
P(initial) = (P(final)V(final))/V(initial)
P(initial) = ((90kPa)(75cm³))/20cm³
P(initial) = 337.5kPa ~ 338kPA
Which of the following molecules does not have a permanent dipole?
A CF4
B CHF3
C CH2F2
D CH3F
Explain please ❤️
Answer:
I think no b
Explanation:
because in chemistry I have nothing listen
CHF3
help me please I will mark as brainliest for the first correct answer
Answer:
1. 3-methylpentane
2. 2-bromo-3-chloropentane
3. 2,2,4-trimethylpentane
Explanation:
1. CH3CH2CH(CH3)CH2CH3.
Methyl group is in the third carbon atom in the long chain. The organic compound has five(5) carbon atoms thus it is named as pentane.
Therefore the name of the compound is
3-methylpentane
2. CH3CH(Br)CH(Cl)CH2CH3
The compound has Chlorine and Bromine in the carbon chain. Chlorine is given as chloro-, Bromine is given as bromo, depending on the position in the carbon chain. Bromine is located in 2 carbon atom and chlorine is in third(3) carbon atom in the long chain. The long chain has five carbon atoms thus pentane.
Naming of the compound we begin with the on lowest in the alphabet. The name of the organic compound is therefore;
2-bromo-3-chloropentane
3. CH3CH(CH3)3CH(CH3)CH2CH3
In this long chained organic compound, methyl-group is found in 2,2 and 4th positions. Since this is still pentane, naming the organic compounds, we start with the one with the lowest carbon. Therefore this becomes;
2,2,4-trimethylpentane
I hope this helps you to know how to name the organic compounds.
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How many neutrons are present in 4.4 gram of Co2
Explanation:
hope it will help you Mark me as a brilliant
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Which among the following mixtures will show tyndal effect?
i) copper sulphate solution
ii) sand in water.
iii) milk.
iv) starch solution
Answer:
milk and starch solution are the colloids, hence these will show the tyndall effect
Answer:
milk and starch solution
Explanation:
Tyndall effect is shown by colloidal solutions. It is not shown by true solutions or suspensions.
Milk and starch solution are colloidal solutions. They show tyndall effect. On the other hand, common salt and copper sulphate solution are true solutions. They do not show tyndall effect.
Question 3 of 10
How are prefixes used to name compounds?
O A. Prefixes are used to indicate the number of atoms in both
covalent and ionic compounds.
O B. Prefixes are used to tell how many of each kind of atom are in
covalent compounds.
O C. Prefixes are used to tell how many of each kind of atom are in
ionic compounds.
O D. A prefix is used only for the name of the second element in
covalent compounds.
the answer is highly possible to be C
Prefixes are used to indicate the number of atoms in both
covalent and ionic compounds.
Covalent or molecular compounds form when elements share electrons in a covalent bond to form molecules. Molecular compounds are electrically neutral.
Ionic compounds are (usually) formed when a metal reacts with a nonmetal (or a polyatomic ion). Covalent compounds are formed when two nonmetals react with each other. Since hydrogen is a nonmetal, binary compounds containing hydrogen are also usually covalent compounds.
Metal + Nonmetal —> ionic compound (usually)Metal + Polyatomic ion —> ionic compound (usually)Nonmetal + Nonmetal —> covalent compound (usually)Hydrogen + Nonmetal —> covalent compound (usually)Learn more about covalent and ionic compounds.
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Answer the following questions based on the above graph(Electron affinity vs Atomic no.)
i)Why on moving from Li to Be, the value of electron gain enthalpy drops.
ii)Cl has a higher peak than fluorine. Explain.
iii)Why Fluorine has the highest value among its period members.
i) Be has a fully filled 2s level.
ii) This is because chlorine is larger than fluorine.
iii) Fluorine needs only one electron to attain the octet configuration.
Electron affinity is the ability of an electron to accept gaseous electrons to yield gaseous ions with a negative charge.
Electron affinity depends on the size of an atom. Larger atoms have a higher electron affinity because they are better able to accept electrons.
The drop between Li and Be is because the 2s orbital in Be is already fully filled while Li has incompletely filled 2s level. electrons do not easily go into the higher energy 2p level.
The higher peak of chlorine is because chlorine is larger than fluorine hence the electron affinity of fluorine is less than that of chlorine. The smaller the ion the lesser the electron affinity.
Fluorine has the highest electron affinity in period 2 because it needs only one electron to attain the octet structure.
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Atom A and Atom B have the same number of protons and neutrons, but they do not have the same number of electrons. ASAP
Answer:
They will be considered ions of the same element.
Explanation:
Ions form from elements when they gain or loss an electron, causing the number of protons (positively charged) to be unequal to the number of electrons (negatively charged), resulting in a net charge.
If there are more electrons than protons (from an element gaining 1 or more electrons), the ion is negatively charged and is called an anion.
If there are more protons than electrons (via the loss of electrons), the ion is positively charged and is called a cation.
difference between peak, orbit and orbital
Answer:
An orbit is a fixed path on which electrons revolve around the nucleus. An orbital is the probable area of finding the maximum density of electrons in an atom. An orbit is a planar representation, i.e., a two dimensional representation.
Cho các dung dịch: Glucozơ, glixerol, fomanđehit, etanol. Có thể dùng thuốc thử nào sau đây để phân biệt được cả 4 dung dịch trên?
A. Cu(OH)2; B. Dung dịch AgNO3 trong NH3;
C. Na kim loại; D. Nước brom.
Xem thêm tại: https://loigiaihay.com/bai-2-trang-25-sgk-hoa-hoc-12-c55a8069.html#ixzz71KH6guhm
Answer:
chắc là câu B í
Explanation:
3.
Melting point of four solids A, B, C and D are 299 K, 111K, 150K, 340K.their inter
particle forces of attraction are in the order:
(a) A
(b) B
(c) C
(d) B
Answer:
You have provided wrong option.
Their interparticle forces of attraction are in the order D>A>C>B
So, option (d) D should be there.
describe two ways in which gases are similar to liquids in properties
Answer:
they have weak intermolecular forces
In a chemical equation, the symbol that means "dissolved in water" is _____. (s) (l) (aq) (g)
If an object is travelling 25.0 meters/second, how far will it travel in 45 minutes?
[tex]\\ \rm\longmapsto Distance=Speed(Time)[/tex]
[tex]\\ \rm\longmapsto Distance=25(2700)[/tex]
[tex]\\ \rm\longmapsto Distance=67500m[/tex]
The object travelling at 25 m/s, will travel a distance of 67500 m in 45 mins.
We'll begin by converting 45 mins to seconds. This can be obtained as follow:1 min = 60 s
Therefore,
45 mins = 45 × 60
45 mins = 2700 sFinally, we shall determine the distance travelled by the object in 2700 s (i.e 45 mins). This can be obtained as follow:Time = 2700
Speed = 25 m/s
Distance =?Distance = speed × time
Distance = 25 × 2700
Distance = 67500 mTherefore, the object will cover a distance of 67500 m in 2700 s (i.e 45 mins)
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The diameter of neutral atoms generally decreases going left to right across one period on the periodic table. What change causes this decrease in diameter of atoms?
Explanation:
Atomic size gradually decreases from left to right across the periodic table because within a period of elements, all electrons are added to the same shell. However, at the same time, protons are being added to the nucleus, making it more positively charged. The effect of increasing proton number is greater than that of the increasing electron number. Therefore, there is a stronger nuclear attraction. This means that the nucleus attracts the electrons more strongly, pulling the atom's electron shells closer to the nucleus. As a result, the atomic diameter of the atom decreases.
What are the problems of turbid water for aquatic plants?
Answer:
Turbidity affects the growth rate of algae (micro-aquatic plants) and other aquatic plants in streams and lakes because increased turbidity causes a decrease in the amount of light for photosynthesis. Turbidity can also increase water temperature because suspended particles absorb more heat.High levels of turbidity can affect aquatic life in several ways.
Too much turbidity might make it difficult for plants to complete photosynthesis, which in turn affects the amount of dissolved oxygen.Fish cannot see well in turbid water making finding food difficult.High turbidity reduces the penetration of sunlight into water and can limit photosynthesis and hence the growth of aquatic plants.Explanation:
Turbidity is the measure of relative clarity of a liquid. The higher the intensity of scattered light, the higher the turbidity. Material that causes water to be turbid include clay, silt, very tiny inorganic and organic matter, algae, dissolved colored organic compounds, and plankton and other microscopic organisms
Convert 50 m to mm
using the method of dimensional analysis
Answer:
Explanation:
meters has to go on the bottom of the bracket used for conversion
50m [ 1000 mm / 1 m]= 50000 mm The meters cancel
Can you help me on this. I will support your correct answer
In Rutherford experiment some alpha particles fired at a gold foil bounced backward as a result of ... A.reflection from the surfaces of gold atoms B.electrostatic repulsion by gold nuclei C.electrostatic repulsion by electronsD.all of the aboveE.none of the above
Answer:
B.electrostatic repulsion by gold nuclei
Explanation:
According to Rutherford's experiment, a thin gold foil was bombarded with alpha particles. Some of the particles passed through the foil undeviated, some were scattered through large angles while some bounced backwards.
It follows that the particles that bounced backwards must have encountered a massive particle of like charge.
The atom is composed of a nucleus which contains positively charged particles. Some of the alpha particles which are positively charged particles bounced back when they encountered the positively charged particles in the nucleus.
Answer: The correct option is B (electrostatic repulsion by gold nuclei).
Explanation:
In the Rutherford's experiment, he used positively charged particles called alpha particles to bombard an atom in order to find out what is inside the atom. Together with two other scientists, Geiger and Marsden, they used a narrow beam of alpha particles emitted from a radioactive source to bombard a thin gold foil. The scattering of the particles from the gold foil was detected by a movable zinc sulphide screen which could be rotated to various positions around the foil.
Each time an alpha particle hit the screen, a visible flash of light or scintillation was produced. This was observed by a microscope attached to the screen. It was then observed that some of the particles followed a straight path through the gold foil while a few where scattered in a backward direction. This was as a result of electrostatic repulsion by gold nuclei which occurs due to the greater part of the mass of the atom was concentrated in a minute nucleus with positive charge.
Describe all the types of chemical reactions with example.
what is filtration? ㅜㅜ ㅜㅜ
Answer:
filtration is the process of using a filter to remove solids from liquids or gasses.
Example:
an example of this is tea.
h2o how many molecules
Answer:
1 mole H2O has 6.02 × 10^23 molecules
Explanation:
1.Which of the following forms only Ionic Bond?
1)Ca 2)C 3)Si 4)P
2.How many atoms of Na are present in 92 a.m.u of it?
a)4 b)5 c)6 d)7
The Answer is A)4 atoms of NA are present in 92 a.m.u
How the amount of acid rain caused by the burning of fossil fuels can be reduced ?
Answer:
The amount of acid rain caused by the burning of fossil fuels can be reduced by creating nitrogen oxides in the process of burning coal and other fossil fuels, some power plants are changing the way they burn coal. A great way to reduce acid rain is to produce energy without using fossil fuels. Instead, people can use renewable energy sources, such as solar and wind power.
difference between Nitrogen 1 oxide and Oxygen
Answer:
one atom of oxygen is not equal to oxygen
