Answer:
hope it helps...
Explanation:
Atomic Number as the Basis for the Periodic Law
Assuming there were errors in atomic masses, Mendeleev placed certain elements not in order of increasing atomic mass so that they could fit into the proper groups (similar elements have similar properties) of his periodic table.
How many grams of calcium are made up by 2.68 x 1023 atoms?
Answer:
Mass = 17.8 g
Explanation:
Given data:
Number of atoms of Ca = 2.68 × 10²³
Mass in gram = ?
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
2.68 × 10²³ atoms × 1 mole /6.022 × 10²³ atoms
0.445 mol
Mass in gram;
Mass = number of moles × molar mass
Mass = 0.445 mol × 40 g/mol
Mass = 17.8 g
All bonds in alkanes, alkenes, and alkynes can freely rotate at room temperature. True or false?.
The statement that all bonds in alkanes, alkenes, and alkynes can freely rotate at room temperature is false.
Alkanes are saturated hydrocarbons with single covalent bonds. All bond in alkanes can freely rotate.
For example, propane is a three carbon alkane (acyclic saturated hydrocarbon).
Chemical formula for the molecule of propane is CH₃-CH₂-CH₃.
Alkenes and alkynes are unsaturated hydrocarbons. Alkenes have one double bond between carbon atoms, while alkynes have one triple bond between carbon atoms. There is no free rotation in double and triple bonds.
R₂C=CR₂ is general formula for the alkenes.
R–C≡C–R is general formula for the alkynes.
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Use the periodic table to choose the element that matches each description.
halogen:
group IIA:
nonreactive:
alkali metal:
Halogen-fluorine,chlorine,bromine,iodine
Group II A- Beryllium,magnesium,calcium,strontium ,barium ,radium
Non-reactive- Helium,neon,argon,krypton,xenon,radon
Alkali metal-lithium ,sodium,potassium,rubidium,caesium,francium.
What is periodic table?It is a representation of chemical elements in a tabular format.It is a graphical representation of modern periodic law which states that the properties of elements are a periodic function of their atomic numbers.
The periodic table is divided into 4 blocks, rows of the table are called periods and columns are known as groups. Elements belonging to the same group show same properties.
First periodic table developed and accepted was by Russian chemist Dmitri Mendeleev in 1869.He formulated the periodic law as properties of the elements are a periodic function of their atomic masses.
Till date 118 elements have been discovered and all have been successfully placed in the periodic table based on their properties.
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Answer:
Use the periodic table to choose the element that matches each description.halogen:
✔ iodine✔ magnesium
✔ argon ✔ potassium
How many moles in 28 grams of CO₂?
Answer:
I think the answer Is 0.636 mol of CO2!
......Please help.....
Answer:
A
Explanation:
If you travel 10 miles in 5 minutes, what is your speed
Answer: 120 mph or 2 mpm
Explanation: 60/5= 12
12*10=120mph
Going 10 miles in 5 minutes means you would be able to go 20 miles in 10 minutes. You would have a total of 12 five minute blocks at 10 miles each. 60 miles in 30 minutes or 120 in 60 minutes.
Or 10 miles in 5 minutes would be 2 miles in 1 minute. (10/5=2)
A consequence of burning fossil fuels is
warming.
Which of the following describes an air mass with the symbol cT?
a.
it is a cold air mass over an ocean
c.
it is a warm air mass over an ocean
b.
it is a warm air mass over a continent
d.
it is a cold air mass over a continent
Please select the best answer from the choices provided
A
B
C
D
Answer:
b
Explanation:
i took the test edg2021
Answer:
b.
it is a warm air mass over a continent
Explanation:
PLZZ HELP QUICK WORTH 20 POINTS IM NOT JOKING PLZZZ
The events taking place in two different locations are described below:
Location A: An oceanic plate collides with a continental plate
Location B: Lithospheric plates move apart below the ocean
In which location will subduction most likely take place and why?
Location B, because divergent plates cause subduction
Location B, because seafloor spreading causes subduction
Location A, because the oceanic plate and continental plate are pushed up together
Location A, because the lighter oceanic plate will be pushed under the continental plate
Answer:
is a
Explanation: A, because the oceanic plate and continental plate are pushed up together
Location A, because the lighter oceanic plate will be pushed under the continental plate
Answer:
is a
Explanation:
Answer:
location A
Explanation:
Plates Subduct When an ocean plate collides with another ocean plate or with a plate carrying continents, one plate will bend and slide under the other. This process is called subduction. A deep ocean trench forms at this subduction boundary.
plus location B doesn't seem to have 2 plates colliding to cause subduction in the first place.
your welcome
Write the full electron configuration for a neutral atom with 22 electrons.
Answer:
1s2 2s2 2p6 3s2 3p6 3d2 4s2
Explanation:
An oxide of iron is found to be 77. 75% iron by mass. Determine the empirical formula for this compound and name it.
The empirical formula of oxide of iron is Fe2O2 and its name is iron oxide.
Given:
Percentage of iron by mass = 77. 75 %Molar mass of iron = 55.85Percentage of oxygen by mass = 22.25 %Molar mass of oxygen =16Solution:
Now, calculate the relative mass of iron in iron oxide = Percentage of iron by mass / At. mass of iron
Relative mass of iron = 77.75/55.85 = 1.39
Relative mass of oxygen = Percentage of oxygen by mass / At. mass of iron = 22.25/16 = 1.39
Now the calculate the molar ratio of iron to oxygen = 1.39 : 1.39 = 2:2
Thus, the empirical formula of iron oxide is Fe2O2 and its name is iron oxide.
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A block of pine wood, 4.0cm on each side, has a mass of 27g. What is the density of this block?
Density is defined as the mass divided by volume.
Density is also known by the name of viscosity.
Density is denoted by D.
It's unit is basically denoted by kg/m^3.
The density of the block is 0.42 g/cm^3.
The formula of the density is, Density = mass (m) / volume (v)
Now, it is given in the word problem that,
Mass of pine wood = 27g
Volume = 4^3 = 64 cm^3
Thus, Density = 27 g /64 cm^3 = 0.42 g/cm^3.
Hence, the density of the block of pine would be 0.42 g/cm^3
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The half life of a radioactive element is 20 days. How many days will it take for the radioactive sample to decay to 1/8 its size?
Answer: 40 days
Explanation: The substance completely disintegrates in 20 days the substance completely disintegrates in 40 days 1/8 part of the mass of the substance will be left intact at the end of 40 days.
Can someone please please help me with the first two !!!! I really need to turn this in !!!!!
Answer:
Be Electron configuration: 1s2 2s2
Be Orbital Diagram: \//\ \//\ (it would be little arrows going up and down to show the spins)
F Electron Configuration: 1s2 2s2 2p5
F Orbital Diagram: \//\ \//\ \//\ \//\ \/
Sodium and chlorine combine to form sodium chloride, or table salt. Sodium and chlorine are:
A: Producers
B: Products
C: Reactionaries
D: Reactants
A chemical reaction is the combination of two or more elements or compounds to form one or more products. The combining compounds or elements are called reactants. Hence, sodium and chlorine are reactants. Thus option D is correct.
What is a chemical reaction?A chemical reaction is a change in the chemical composition that occurs when two or more species unite to create a new product by forming or breaking chemical bonds.
The reactants are the organisms that are reacting. In a reaction's chemical equation, they are shown on the left side. The right side of the arrow is where the products are shown.
Consider the reaction of sodium and chlorine to give NaCl.
Na + Cl ⇒ NaCl.
NaCl is the product in this reaction. Na and Cl are the reactants. Hence, option D is correct.
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Which phrase best describes earths atmosphere
A. A single layer of gases surrounding earth
B. multiple layers of gases surrounding earth
C. A bubble of air close to the surface of earth
D. Clouds and particles in a single layer around earth
Answer:
b
Explanation:
Earth's atmosphere is composed of multiple layers of gases surrounding earth. So the correct option is B.
What is the atmosphere?The atmosphere of Earth extends from the planet's surface up to 10,000 kilometres (6,214 miles) above. Following that, the atmosphere disappears into space. Although there is disagreement among scientists on the location of the atmosphere's upper border, most of them can agree that the atmosphere's majority is found near the planet's surface, up to a distance of around eight to fifteen kilometres (five to nine miles).
While most life on Earth requires oxygen, oxygen does not make up the bulk of the planet's atmosphere. About 78% of the gases in the Earth's atmosphere are nitrogen, 21% are oxygen, 0.9 % are argon, and 0.1 % are other gases. The remaining 0.1 per cent of gases includes trace quantities of neon, water vapour, methane, carbon dioxide, and methane.
Based on temperature, the atmosphere is separated into five distinct strata. The troposphere, which is located between five and ten miles (or seven and 15 kilometres) above Earth's surface, is the layer that is closest to the surface. The troposphere is significantly thinner near the North and South Poles than it is at the equator. The troposphere, which makes up between 75 and 80 per cent of the total atmosphere, is where the majority of its mass is located.
Therefore the correct option is B.
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Why does a bronze bell sound better than a tin bell?
If an ice cube is melting identify the property of the substance that is change.
If an ice cube is melting, its shape and state of matter changes from solid to liquid, while its chemical composition remains the same. Hence, it is a physical change.
When an ice cube melts, only the physical property of the ice cube changes. No new substances are formed, and the chemical composition of the ice does not change, making it a physical change.
A physical change occurs only the physical properties of the substance like colour, shape, density and solubility changes. It is easily reversible. The melted ice can easily be re-frozen back to its solid state. Also, the melting process does not produce any new chemical substance.
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n‑methyl‑2‑pyrrolidone is an aprotic solvent used in many industrial processes. draw the structure of the product formed when it is heated with aqueous acid. n methyl 2 pyrrolidone is a 5 membered ring consisting of 4 carbons and one nitrogen. the nitrogen is bonded to a methyl group. the carbon next to the methyl group is double bonded to an oxygen atom. this reacts with h plus, water and heat.
N-methyl-2-pyrrolidone is a very reactive compound. It reacts in an acidic medium to form a variety of products. Some reactions involve the ring-opening step.
The structure of N-methyl-2-pyrrolidone is given below:
The compound has a five-membered ring, which consists of four carbon atoms and one nitrogen atom. The ring has one oxygen attached to it via the double bond, and one methyl group is attached to the nitrogen atom.
The chemical reaction involved is as follows:
The structure of the product is given below:
N-methyl-2-pyrrolidone on reaction with strong aqueous acidic medium followed by the treatment of heat results in the opening of the ring and forms a compound having a carboxylic group at one end and protonated nitrogen atom which has one methyl group attached to it, at another end
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a solution of 5 m hcl is already made. you need to dilute the solution to 1 m hcl. the 1 m hcl solution is . slower
"A solution of 5 M HCl is already made. You need to dilute the solution to 1 M HCl. The 1 M HCl solution is less concentrated." Thus, option b is correct.
What is molar concentration?Molar concentration has been the molarity of the solution that measures the amount of the solute present in the liter solution. It describes the solute concentration that depends on the volume.
The dilution of the solution by increasing the volume results in a decrease in the concentration as molarity and volume show an inverse relationship. So, 1 M is less concentrated than 5 M solution.
Therefore, option b. less concentrated is the correct blank.
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Your question is incomplete, but most probably your full question was, A solution of 5 M HCl is already made. You need to dilute the solution to 1 M HCl. The 1 M HCl solution is ____________.
a. more concentrated
b. less concentrated
c. neither
d. both less and more concentrated
Green energy may also be referred to as renewable or clean energy.
True
False
What is the wavelength of a wave having a frequency of 3.23 x 10^14 s-1
Answer:
λ =0.93×10⁻⁶ m
Explanation:
Given data:
Wavelength of wave = ?
Frequency = 3.23 ×10¹⁴ s⁻¹
Solution:
Formula:
Speed of wave = frequency × wavelength
speed of wave = 3×10⁸ m/s
by putting values,
3×10⁸ m/s = 3.23 ×10¹⁴ s⁻¹ × λ
λ = 3×10⁸ m/s / 3.23 ×10¹⁴ s⁻¹
λ =0.93×10⁻⁶ m
25.00 grams of sodium chloride reacts with an excess
hydrochloric acid and sodium sulfate. What weight of HCl is produced?
Mass of HCl produced :15.59 g
Further explanationReaction
2NaCl + H₂SO₄ → 2HCl + Na₂SO₄
Excess = H₂SO₄
Limiting = NaCl
mass NaCl = 25 g
mol NaCl(MW=58.5 g/mol) :
[tex]\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{25}{58.5}=0.427[/tex]
From the equation, mol ratio NaCl : HCl = 2 : 2, so mol HCl = mol NaCl =0.427
Mass of HCl(MW=36.5 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass=0.427\times 36.5\\\\mass=15.59~g[/tex]
Sebastian watches his cat run out Into the yard, look at a bug, and then run back to the
house.
Between which two points is the cat's Motion showing No Motion?
The Cat's Position vs. Time
Position
G
Time
A. Points A to B
B. Points B to C
C. Points C to D
D. Points D to E
Answer:
I think its A
Explanation:
what stages would a low mass star pass through in its lifetime
Answer:
Low mass star phases
Explanation:
Helium fuses into carbon, the core of the star collapses. Once this happens, the outer layers become exhausted from the weight and this leads a planetary nebula to be formed from the outer layers. The core of the star remains a white dwarf for some time, but eventually it cools down and evolves to a black dwarf.
In pea plants, yellow seeds are dominant to green seeds. A heterozygous yellow-
seeded pea plant (Yy) is crossed with a plant that has green seeds (yy). What
would be the phenotype % in having yellow or green seeds.
Your answer
Answer:
The phenotypic percentage of having yellow or green seeds is 50% for having either of the two colours
Explanation:
The crossing to determine the offsprings is shown in the image attached where we have two green (Yy) seeds and two yellow (yy) seeds as offsprings.
Thus, the phenotypic percentage of having yellow or green seeds is 50% for having either of the two colours.
Note, the dominant allele is "Y" while the recessive allele is "y". Thus, Yy would produce a yellow colour while yy would produce a green colour (as both mentioned in the question).
Also note that phenotype describes the outward properties/characteristics of an individual.
what reaction type is the followong reaction
Answer:
its the fourth one please mark as brainlest
Explanation:
ill mark brainliest plz help
Answer:
option d
Explanation:
please mark me brainliest
Answer: S₅Br₆
Explanation: The prefix “penta-“ means five, and the prefix “hexa-“ means six.
Which end of the H-F molecule will be partially positive?
neither end
the fluorine end
both ends
the hydrogen end
Answer:
the hydrogen end
Explanation:
In H - F molecules there is a charge separation. Hydrogen has partial positive charge on them and Fluorine has a partial negative charge on it.
The bonds between H - F molecule is a covalent bond. In this bond, both atoms share their electrons to attain a stable configuration But the electrons are not shared equally. Fluorine is more electronegative compared to the hydrogen. Fluorine therefore, attracts the shared electrons more closely to itself. This makes fluorine more negative and hydrogen positive.Can someone help me please?
Answer:
D. 10mm = 1 cm
E. 1000m = 1mm
G. 100 cm = 1 m
H. 1 m = 10 dm