Answer:
C the breaking down of rock
Answer: option C. the breaking down of rock
Explanation: weathering is the breaking down of rock by the action of rain, temperatures and biological activities.
after 40 days have passed, how many grams of a 250-g sample of thorium-234 would remain?
78.78 g out of 250 g of Thorium-234 would remain after 40 days.
Explanation:
All radioactive samples are unstable in nature and so they will be decaying with time. So the equation of disintegration of the radioactive element is given as
[tex]N=N_{0}e^{-kt}[/tex]
So N is the mass of the radioactive element at time t and [tex]N_{0}[/tex] is the mass of the radioactive element at initial stage. Here k is the disintegration constant and t is the time.
We can determine the disintegration constant from the half life term of any element.
[tex]Half life = \frac{0.693}{k}[/tex]
So, [tex]k = \frac{0.693}{Half life}[/tex]
Since, the half life time of thorium-234 is known to be 24 days. Then, the disintegration constant is
[tex]k = \frac{0.693}{24}=0.028875[/tex] [tex]days^{-1}[/tex]
As the given questions have the initial mass [tex]N_{0}[/tex] as 250 g and t is given as 40 days, then the mass after 40 days will be
[tex]N = 250 * e^{-0.02887*40}= 250 * e^{-1.1548}=78.78 g.[/tex]
Thus, 78.78 g of thorium-234 would remain after 40 days.
To determine how many grams of thorium-234 would remain after 40 days, we need to understand the concept of radioactive decay. Using the formula for remaining mass, the approximate remaining mass would be 28.69 grams.
Explanation:To determine how many grams of thorium-234 would remain after 40 days, we need to understand the concept of radioactive decay. Thorium-234 undergoes radioactive decay with a half-life of 24.1 days. This means that after 24.1 days, half of the thorium-234 sample would decay.
To calculate the remaining grams after 40 days, we can use the following formula:
Remaining mass of thorium-234 = Initial mass × (1/2)^(number of half-lives)
Substituting the values, we have:
Remaining mass of thorium-234 = 250 g × (1/2)^(40/24.1)
Using a calculator, the remaining mass of thorium-234 after 40 days would be approximately 28.69 grams.
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Give an example of a solution that can be seperated by simple distilation.
Answer: Evaporation of salt water
Explanation: During the process of evaporating salt water which involves simple distillation, pure water is separated with salt molecules.
When heated water evaporates from the solution since it is less dense. When condensed it becomes pure water and salt is left out since it is more denser.
How do you balance a chemical reaction?
Answer:
write down the number of atoms in each element, which is listed in the subscript next to each atom. Then, add coefficients to the atoms on each side of the equation to balance them with the same atoms on the other side.
Explanation:
Final answer:
To balance a chemical equation, write the correct formulas, count the atoms of each element, adjust coefficients to balance the atoms, use polyatomic ions as units, eliminate fractional coefficients for whole numbers, and check that all elements are balanced.
Explanation:
To balance a chemical reaction, one must ensure that the number of atoms for each element is equal on both sides of the equation. This is key to upholding the law of conservation of mass. The following steps are a simplified guide:
Write the skeleton equation with the correct formulas for reactants and products.
Count the number of atoms of each element in the reactants and in the products.
If the equation is not balanced, adjust the coefficients before the formulas, not the subscripts within them, to balance the atoms of each element.
Balance polyatomic ions as a unit if they appear unchanged on both sides of the equation.
Use fractional coefficients if necessary, and then multiply the entire equation to eliminate fractions and have whole number coefficients.
Perform a final check to ensure that all elements are balanced.
Throughout this process, one may use a trial-and-error approach to fine-tune the balancing, adjusting coefficients as needed until the number of atoms for each element is the same on both sides of the equation.
When an ion is positive is has____ electrons
Answer:
When an ion is positive is has "more protons than" electrons
Explanation:
In case of an atom when gets involved with other atom due to uneven nos. of electrons and the protons, the atom formed is known as the ion. When, the atom has higher number of electrons than that of the protons it will form an negative ion. Bt in case of more number of protons as compared to the electrons it will form a positive ion. The ion with positive charge is basically called as the cation, with negative charge called as anion.
how manymoles are in 7.6g of ca
Answer: 0.19mol
Explanation
Mass of Ca = 7.6g
Molar Mass of Ca = 40g/mol
n = Mass /Molar Mass = 7.6/40
n = 0.19mol
Which effects would many organisms likely experience if global warming occurs? Check all that apply. disrupted food webs increased competition increased number of glaciers disrupted life-cycle events forced relocation
Answer:
Disrupted food webs
increased competition
disrupted life-cycle events
forced relocation
Explanation:
The results of global warming can be devastating for every living organism. Global warming will cause mist of the organisms of a species to die as they will not be able to maintain themselves in such heated environments. As a result, there will be more competition for resources among different organisms. Organisms will be forced to leave their habitats and relocate themselves as a result of global warming.
Answer:
Disrupted food webs
increased competition
disrupted life-cycle events
forced relocation
Explanation:
Which statement correctly describes two organ systems working together when the body increases its movement?
Answer:
Explanation: The respiratory system increases gas exchange, and the circulatory system circulates blood faster to deliver oxygen to muscles.
Jöns Jakob Berzellus _.
developed atomic theory
created the Periodic Table of Elements
proposed the planetary atomic model
Invented the chemical notation system
Answer:
Jöns Jakob Berzellus _
Invented the chemical notation system
Explanation:
Meaning of chemical notation : It is the representation of chemical composition of element by symbols.
Berzelius was the first person to measure accurate atomic weight of the elements, which helped to confirm Dalton's Atomic Theory.
He described how chemical bonds are formed by electrostatic attraction.
Berzelius, work with atomic weight and his theory of electrochemical dualism led to the development of Chemical notation that decide the chemical notation of the compounds.This chemical notation determines about the element both qualitatively and quantitatively.
He identified that compounds can be distinguished by the opposing constituents which are the acidic constituent , the basic and the neutral part.
This formula representation is given by Berzelius.
Answer:
Jöns Jakob Berzellus
Invented the chemical notation system
Explanation:
I got this one right on my test so it is right.
Please help me! And if can explain me the work I would really appreciate it! Thank you!! ❤️
Answer: The answer is D
Explanation:
So there is 2K + 2H2O --> 2KOH + 1H2
2Potassium + 2Water ---> 2Potassium Hydroxide + 1Dihyrogen
Simple diffusion is defined as the movement of
A molecules from areas of higher concentration to areas of lower concentration.
B) molecules from areas of lower concentration to areas of higher concentration.
c) water molecules across a membrane.
b) gas molecules across a membrane.
E) gas or water molecules across a membrane.
Explanation:
Diffusion
It is the movement of substances from the region of higher concentration to lower concentration .
This diffusion is shown almost negligible by solids , a little by liquids and maximum by gases .
The factors on which diffusion depends :
Inter-molecular force between particles : It is inversely proportional to diffusion .That is : more is the force , lesser the diffusion rate Inter-molecular space between particles : More is the space , more is the diffusion or vice versa .Density of substance :More is the density , less is the diffusion or vice versa .Applications of diffusion
It helps in the movement of substance in and out from the cell and its components .
It helps in spreading the fragrance when sprayed with some perfume etc .
It helps in dissolving substance in any medium
Etc
Simple diffusion is the movement of molecules from areas of higher concentration to areas of lower concentration.
Explanation:Simple diffusion is defined as the movement of
molecules from areas of lower concentration to areas of higher concentration.water molecules across a membrane.gas molecules across a membrane.gas or water molecules across a membrane.Simple diffusion refers to the movement of molecules from an area of higher concentration to an area of lower concentration. This process occurs due to the natural tendency of molecules to move from regions of high concentration to regions of low concentration in order to achieve equilibrium. This movement does not require the assistance of any external energy or transport proteins.
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How many grams of NH3 can be prepared from the synthesis of 77.3 grams of nitrogen and 14.2 grams of hydrogen gas?
Answer:
80.41 g
Explanation:
Data Given:
Mass of Nitrogen (N₂) = 77.3 g
Mass of Hydrogen (H₂) = 14.2 g
many grams of NH₃ = ?
Solution:
First we look at the balanced synthesis reaction
N₂ + 3 H₂ ------—> 2 NH₃
1 mol 3 mol
As 1 mole of Nitrogen react with 3 mole of hydrogen
Convert moles to mass
molar mass of N₂ = 2(14) = 28 g/mol
molar mass of H₂ = 2(1) + 2 g/mol
Now
N₂ + 3 H₂ ------—> 2 NH₃
1 mol (28 g/mol) 3 mol(2g/mol)
28 g 6 g
28 grams of N₂ react with 6 g of H₂
So
if 28 grams of N₂ produces 6 g of H₂ so how many grams of N₂ will react with 14.2 g of H₂.
Apply Unity Formula
28 g of N₂ ≅ 6 g of H₂
X g of N₂ ≅ 14.2 g of H₂
Do cross multiply
X g of N₂ = 28 g x 14.2 g / 6 g
X g of N₂ = 66.3 g
As we have given with 77. 3 g of N₂ but from this calculation we come to know that 66.3 g will react with 14.2 g of hydrogen and the remaining 10 g N₂ will be in excess
So, Hydrogen is limiting reactant in this reaction and the amount of NH₃ depends on the amount of hydrogen.
Now
To find mass of NH₃ we will do following calculation
Look at the reaction
As we Know
N₂ + 3 H₂ ------—> 2 NH₃
6 g 2 mol
So, 6 g of hydrogen gives 2 moles of NH₃, then how many moles of NH₃ will be produce by 14.2 g
Apply Unity Formula
6 g of H₂ ≅ 2 mol of NH₃
14.2 g of H₂ ≅ X mol of NH₃
Do cross multiply
X mol of NH₃= 14.2 g x 2 mol / 6 g
X mol of NH₃ = 4.73 mol
So, 14.2 g of hydrogen gives 4.73 moles of NH₃
Now
Convert moles of NH₃ to mass
Formula will be used
mass in grams = no. of moles x molar mass . . . . . . (2)
Molar mass of NH₃
Molar mass of NH₃ = 14 + 3(1)
Molar mass of NH₃ = 14 + 3 = 17 g/mol
Put values in equation 2
mass in grams = 4.73 mole x 17 g/mol
mass in grams = 80.41 g
mass of NH₃= 80.41 g
Using the principles of stoichiometry, it can be calculated that while 77.3 grams of nitrogen could produce 93.5 grams of NH3, the 14.2 grams of hydrogen can only generate 80.6 grams of NH3. Hence, the reaction is limited by hydrogen and can only yield 80.6 grams of NH3.
Explanation:To figure out how many grams of NH3 can be prepared from 77.3 grams of nitrogen and 14.2 grams of hydrogen gas, you need to use the stoichiometry principle in chemistry which refers to the calculation of quantities in a chemical reaction.
The balanced chemical equation for the formation of ammonia is: N2 + 3H2 -> 2NH3. From this equation, we see that 28 grams of nitrogen (N2) react with 6 grams of Hydrogen (H2) to produce 34 grams of ammonia (NH3). Therefore, for 77.3 grams of N2, it would form (77.3/28)*34 = 93.5g of NH3 if there is sufficient H2.
However, we only have 14.2 grams of H2. Given the stoichiometry of the reaction we know that 6 grams of H2 can produce 34 grams of NH3, so 14.2 grams of H2 will produce (14.2/6)*34 = 80.6g of NH3. Hence, the amount of NH3 that can be produced is limited by the amount of H2, and only 80.6 grams of NH3 can be synthesized.
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What do scientists generally do if they are NOT sure what the expected value of a measurement should be? A. use their best estimate for the true value B. stop the experiment and measure something else C. take the expected value from a different experiment D. decide not to measure the accuracy of the experiment
Answer: A
Explanation: Use their best estimate for the true value
Carole owns a two story house with a heating and cooling unit on each floor. In the winter she mostly uses the downstairs unit because the volume of warm air __________ and __________ warming the whole house through __________.
A) expands, rises, convection
B) expands, sinks, conduction
C) contracts, rises, conversion
D) contracts, sinks, contraption
Which of the following most likely happens when astronauts go to space?
1. Their heart rate speeds up because the blood vessels have less blood to circulate.
2. Their heart rate speeds up because the blood vessels have more blood to circulate.
3. The blood vessels in their neck caves in because the heart pumps less blood per beat.
4. The blood vessels in their neck bulges out because the heart pumps more blood per beat.
Answer:
4. The blood vessels in their neck bulge out.
Explanation:
This option is closest to being correct.
On Earth, the force of gravity pulls blood to the lower body. In space, the force of gravity is cancelled, so the blood spreads out evenly.
More blood in the upper body leads to increased blood pressure there, so the blood vessels in the neck bulge out.
The heart does not pump more blood per beat. Instead, it becomes lazy because it does not have to do as much work pumping blood back from the legs against the force of gravity.
A and B are wrong. You don't gain or lose blood simply by going into space.
C is wrong. The blood vessels in the neck bulge out.
The blood vessels in their neck bulge out because the heart pumps more blood per beat most likely happens when astronauts go to space.
Does the universe affect blood flow?In microgravity, the heart transforms from an elliptical shape (like a balloon filled with water) to a round sphere (a balloon filled with air), and the universe causes atrophy of the muscles that work on Earth and blood vessels. Shrinks. Nor can it control blood flow.
There are completely different results in the universe. There is no gravity that draws blood into the lower body. Instead, blood flows into the chest and head, the astronaut's face swells, and the blood vessels in the neck swell. And appearance isn't the only ugly side effect.
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There are four distinct techniques used to separate mixtures described in this lesson. Name and describe each technique.
Explanation:
Mixtures
They are formed when two or more substances are simply mixed in any ratio not chemically combined with each other.
Characteristics
They can be homogeneous or heterogeneous in nature that is the constituents can be seen to have visible boundaries or they may appear to mix thoroughly. The Properties of mixtures are same as that of constituents. The constituents can be separated by physical methods. Their formations do not require or release energy as there is no bond formation or breakage involved. The Properties of mixtures like melting point & boiling points are not fixed.Let us discuss few techniques :
1. Evaporation
For example :To obtain colored component (Dye) from Ink
Materials Required : Watch glass ink (blue/ black) beaker , stand, burner.
Procedure :
Take a beaker and fill it half with water. Take ink (Blue/ black) in the watch glass and place it on the mouth of the beaker Start heating the beaker and observe. Heating is continued as long as the evaporation is taking place Heating is stopped when no any further change can be noticed on the watch glassObservation:
Evaporation taking place from the watch glass can be seen
Residue is left on the watch glass
Conclusion drawn :
it can be concluded that ,”Ink is not a pure substance but it is a mixture of dye in water which can easily be separated by evaporation method”. Ink is not a single substance2, Centrifugal method
For example : To separate cream from milk by using centrifuge method.
Materials Required : Full cream milk centrifuging machine/milk churner, jug test-tubes.
Procedure:
Take un-boiled cold milk in two test-tubes and place these test-tubes in a centrifuging machine Centrifuge it at high speed by using a hand centrifuging machine for two minute and observe.Observation
Cream floating on the milk can be seen.
Conclusion drawn
When milk is rotated at high speed then the suspended lighter particles (fats and protein molecules) bind with each other forming ‘cream’ and ‘skimmed milk’. The cream being lighter floats over the skimmed milk which can be removed easily.
3. Sublimation
For example :To separate a mixture of common salt and ammonium chloride :
Materials Required : China dish, tripod stand mixture of common salt and ammonium chloride glass funnel cotton and burner.
Procedure:
Take the mixture of sand and ammonium chloride in a china dish. Cover the china dish with an inverted glass funnel and place it on a tripod stand. Put a loose cotton plug in the opening of the funnel so as to prevent the escape of ammonium chloride vapors. Heat the china dish on a low flame and observe.Observation :
White fumes (vapors) of ammonium chloride can be seen coming out of the mixture. These white fumes start depositing as white solid on coming in contact with the cold, inner walls of the funnel. Sand salt is left behind in the china dish.Conclusion drawn: Ammonium chloride, being a volatile substance , changes into white vapors easily which deposits on the cold inner wall of the funnel. This ammonium chloride obtained is called the
The simulation shows a quantity of oxygen molecules. What state of matter is this?
Answer:
It should be gas.
Explanation:
It should be gas but I don't see the simulation so it's possible that it's solid/liquid
( Balance each equation) Na + MgF2 NaF + Mg
Answer:
2Na + MgF₂ → 2NaF + Mg
Explanation:
Chemical equation:
Na + MgF₂ → NaF + Mg
Chemical equation:
2Na + MgF₂ → 2NaF + Mg
The given reaction follow the law of conservation of mass because there are equal number of atoms of sodium, magnesium and fluorine are present on both side of equation.
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
This law was given by french chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
Type of reaction:
The given chemical reaction is type of single replacement reaction. Sodium replace the magnesium and form sodium fluoride.
Single replacement:
It is the reaction in which one elements replace the other element in compound.
AB + C → AC + B
Is testing for fingerprints on a door a physical or chemical change
Answer:
Dusting for fingerprints makes use of the physical property of stickiness. Skin oils absorb the fingerprint dust, which is then collected on a sticky tape.
Dusting for fingerprints makes advantage of stickiness as a physical change. Skin oils adsorb the dust from fingerprints.
What is physical change ?Physical modifications are those that modify a chemical substance's shape but not its chemical content. Physical changes are normally unable to divide compounds into chemical elements or simpler compounds, although they can be utilized to separate mixtures into their components.
A physical change happens when a substance's physical characteristics change without undergoing chemical composition. Melting, changes in size, volume, color, and crystal shape are examples of common physical changes.
Thus, the dusting for fingerprints makes advantage of stickiness as a physical change. Skin oils adsorb the dust from fingerprints.
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which one of the following gases is evolved when a mixture of concentrated sulphuric acid, manganese oxide and sodium chloride is warmed?
When a mixture of concentrated sulfuric acid, manganese oxide and sodium chloride is warmed, the chlorine gas is formed.
Explanation:
NaCl + MnO₂ + H₂SO₄ -----> NaHSO₄ + MnSO₄ + H₂O + Cl₂
For balancing the equation
i) 2 Cl atoms are present at right side while 1 atom is present in left side.
Cl atoms get balanced by putting 2 before NaCl.
ii) Now there are 2 Na atoms present at left while 1 atom is present at the right side.
To balance it, put 2 before NaHSO₄.
iii) (SO₄) is 3 units on the right-hand side, 1 on the left-hand side.
Put a 3 before H₂SO₄ on the left-hand side, thus balancing the number of (SO₄) units.
iv) Balance the excess H atoms present at the left side, by putting a 2 before H₂O.
4NaCl + MnO2 + 4H2SO4 ---> MnCl2 + 4NaHSO4 + 2H2O + Cl2
When Manganese oxide reacts with sodium chloride and sulfuric acid, it gets warmed and produces manganese chloride, chlorine gas, sodium bisulfate, and water.
When this mixture is warmed it produces chlorine gas.
The molecular weight of calcium carbonate, CaCO3, is 100.09 3.
mol
How many moles of calcium carbonate are in 63.8 g of calcium carbonate?
Express the answer using 3 significant figures.
Answer:
Number of Moles = Reacting mass / Molecular mass
= 63.8 / 100.09
= 0.637g
Hence, the moles of calcium carbonate in 63.8 g of calcium carbonate is 0.637g
Explanation:
The number of moles of a compound is the ratio of weight given to the molar mass. One mole calcium carbonate is 100.09 g/mol. Then, the number of moles in 63.8 g of calcium carbonate is 0.638 moles.
What is one mole of a substance ?One mole of a substance is its amount containing 6.02 × 10²³ number of its atoms. This number is called Avogadro number. Hence, one mole of any element contains Avogadro number of atoms. The mass of one mole of an element is called atomic mass.
Similarly one mole of any compound contains Avogadro number of molecules. The mass of one mole of the compound is called its molar mass.
Molar mass of calcium carbonate = 100.9 g/mol
given mass = 63.8 g
then, number of moles = 63.8 /100.9 g = 0.693 moles.
Therefore, the number of moles of 63.8 g of calcium carbonate is 0.693 moles.
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will make brainliest if answer correctly.
Why would you expect strontium to be chemically more similar to calcium?
They are in the same family/group.
They are in the same period.
They have the same atomic number.
They have the same atomic mass.
Answer:
They are in the same family/group.
Explanation:
Both Ca and Sr are Group 2 elements, so can be expected to have similar chemical properties. Strontium would be expected to be chemically similar to calcium because they are in the same family/group.
help needed ASAP plz
Answer:
6 cucumberslices.
Explanation:
You can make a maximum of 4 sandwiches. 8 slices of tomato and 2 needed for each. 8/4=2. You need 4 slices of cucumber per sandwich and have 22. the maximum of sandwiches we can make is 4 so 4×4=16. 22-16=6 leftover slices of cucumber.
If an atom gains an electron, what overall charge will it have?
Answer:
The atom will have a negative charge.
Explanation:
Electrons are subatomic particles with a negative charge, protons are subatomic particles with a negative charge, and neutrons have no charge. When a neutral atom's balance is disrupted by an extra electron, the atom becomes negatively charged.
Answer:
it will have a negative charge
Explanation:
What is the mass of 5 miles in ba3n2
Answer:
2200 g
Explanation:
Data Given:
no. of moles of Ba₃N₂ = 5 moles
mass of Ba₃N₂ = ?
Solution:
Formula used
no. of moles = mass in grams / molar mass
To find mass rearrange the above equation:
mass in grams = no. of moles x molar mass. . . . . . (1)
molar mass of Ba₃N₂
molar mass of Ba₃N₂ = 3(137.3) + 2(14)
molar mass of Ba₃N₂ = 412 + 28
molar mass of Ba₃N₂ = 440 g/mol
Put values in equation 1
mass in grams = 5 moles x 440 g/mol
mass in grams = 2200 g
So,
mass of Ba₃N₂ = 2200 g
What is the formula for “ammonium sulfite”
Answer:
(NH₄)₂SO₃
Explanation:
Data Given:
formula for "ammonium sulfite”
Solution
Ammonium sulfite consist of following atoms
Nitrogen = N
Hydrogen = H
Sulfur = S
Oxygen = O
Now we will look for the symbols of ammonium and sulfite
Ammonium = NH₄⁺
ammonium consists one nitrogen and 4 hydrogen atoms. it have overall 1 positive charge.
Sulfite = SO₃²⁻
it have one sulfur and 2 oxygen atoms. the overall charge is 2-.
Now we will write Both ammonium and sulfite ions together. the charges will are the combining power and will be written at the base of the alternate position formula unit.
(NH₄)₂SO₃
So 2 ammonium ions combine with one sulfite ion.
So the formula for “ammonium sulfite” is (NH₄)₂SO₃
The formula of compound that shows the types and numbers of atoms present in a molecule of the compound ammonium sulfite is (NH₄)₂SO₃.
The formula of a compound is a chemical shorthand that provides information about the composition of the compound. The formula typically consists of the atomic symbols of the elements present in the compound, along with subscript numbers indicating the number of atoms of each element.
For example, the formula of water is H₂O, which indicates that it contains two hydrogen (H) atoms and one oxygen (O) atom. Similarly, the formula of sodium chloride is NaCl, representing one sodium (Na) atom and one chlorine (Cl) atom.
The formula of a compound is essential for understanding its chemical properties, stoichiometry, and reactions. It provides a concise way to represent the arrangement of atoms in a molecule and allows scientists to communicate and work with compounds more efficiently.
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Identify the combustion reaction.
a) Al 2S 3 — 2A1 + 35
b) 2H 2 + O2 – 2H 20
c) C12 + 2KBr — 2KCI + Br2
d) C4H 12 + 70 2 - 6H 20 + 4CO 2
Answer:
D) C4H 12 + 70 2 - 6H 20 + 4CO 2
Explanation:
I'm certain this is a combustion reaction.
2
How
12.6
Sn + 2 HF - Snf a + H₂
many moles of tin (11) Fluoride will be produced
grams of hydrogen fluoride react?
if
Answer:
12.6 gram of HF will produced 0.315 moles of SnF₂
Explanation:
Given data:
Mass of HF = 12.6 g
Moles of Tin fluoride produced = ?
Solution:
Chemical equation:
Sn + 2HF → SnF₂ + H₂
Number of moles of HF:
Number of moles = mass/ molar mass
Number of moles = 12.6 g/20.01 g/mol
Number of moles = 0.63 mol
Now we will compare the moles of HF with SnF₂.
HF : SnF₂
2 : 1
0.63 : 1/2×0.63 = 0.315 mol
So 12.6 gram of HF will produced 0.315 moles of SnF₂.
A compound contains 70.18 % oxygen by mass. What mass of this compound would be needed to obtain 48.45 grams of oxygen?
Answer:
69.036 g of Compound is required to obtain 48.45 g of Oxygen.
Explanation:
Let us assume that the total mass of the compound is 100 g. So it means that this compound weighing 100 is composed 70.18 % of Oxygen or among 100 g of this compound 70.18 g is constituted by oxygen only. Hence, we can make a relation as that,
70.18 g O is present in = 100 g of a Compound
So,
48.45 g of O will be present in = X g of a Compound
Solving for X,
X = 100 g × 48.45 g ÷ 70.18 g
X = 69.036 g of Compound
Use the periodic table to determine the electron configuration for Ca and Pm in noble-gas notation
Ca:
Pm:
✓
Ca:
[Ar]4s
[Ar]4s
[Xe]6s2506
[Xe]6s25f4
Pm:
[Xe6s245
[Xe]6s244
[Ar]3s2
[kr]452
Answer:
Ca: [Ar] 4s²
Pm : [Xe} 6s² 4f⁵
Explanation:
The electronic configuation of an element in noble gas notation is written by giving the symbol of the nearest noble gas that is present in the period above it in the periodic table, followed by the electronic configuration of the remaining electrons.
For Ca the atomic no is 20
It is in 4th period.
The electronic configuration of Ca is 1s²2s²2p⁶3s²3p⁶4s²
1s²2s²2p⁶3s²3p⁶ represents the electronic congiguation of Ar with completely filled valence shell. So we can represent electronic configuration of Ca as [Ar] 4s².
The atomic no. of Promethium,Pm is 61. It's electronic configuration is
1s²2s²2p⁶3s²3p⁶4s² 3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f⁵
1s²2s²2p⁶3s²3p⁶4s² 3d¹⁰4p⁶5s²4d¹⁰5p⁶ is the configuration of the noble gas Xe . So we can represent electronic configuration of Pm as
[Xe} 6s² 4f⁵
Answer:
Ca: [Ar] 4s²
Pm : [Xe} 6s² 4f⁵
Explanation:
6.755 mol Pb(SO4)2
How many atoms
Answer: 4.07x 10²⁴ atoms Pb( SO4)2
Explanation: Solution:
6.755 moles Pb(SO4)2 x 6.022x10²³ atoms Pb(SO4)2 / 1 mole Pb(SO4)2
= 4.07x10²⁴ atoms Pb(SO4)2