Which experiment led to the idea that atoms contain a nucleus?
Answer:
Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. Based on these results, Rutherford proposed the nuclear model of the atom.
Explanation:
explain the chemical reaction
A chemical reaction is when reactants are converted into another substance (also called products). Their reaction rearranges the constituent atoms of the reactants to give different substances as products.
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What is the balanced form of the chemical equation shown below?
Ca(OH)2(aq) + Na2CO3(aq) CaCO3(s) + NaOH(aq)
A. Ca(OH)2(aq) + Na2CO3(aq) CaCO3(s) + 2NaOH(aq)
B. 2Ca(OH)2(aq) + Na2CO3(aq) 2CaCO3(s) + 2NaOH(aq)
C. CaOH(aq) + Na2CO3(aq) CaCO3(s) + Na2OH(aq)
D. Ca(OH)2(aq) + Na2CO3(aq) CaCO3(s) + NaOH(aq)
Answer:
B
Explanation:
. 2Ca(OH)2(aq) + Na2CO3(aq) 2CaCO3(s) + 2NaOH(aq)
A. Ca(OH)2(aq) + Na2CO3(aq) CaCO3(s) + 2NaOH(aq)
gases does not have definite shapes and volume ? (give a scientific reason for the following)
Answer:
Gases do not have a definite shape or volume because the molecules in gases are very loosely packed, they have large intermolecular spaces and hence they move around. ... The particles of solid are closely packed and occupy less space while particles of gases are loosely packed and occupy the complete space available.
Explanation:
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Which of the following could be classified as a molecular element?
Question 1 options:
krypton
lithium
nitrogen
calcium
All four are classified as molecular elements.
Answer:
calcium is the correct answer to the question
why is the reaction of Iron and hydrochloric acid slow
Answer:
The chloride formed when iron reacts with hydrochloric acid is iron (II) chloride, also known as iron dichloride. The reaction between iron and hydrochloric acid is slower than the reaction with zinc, with much smaller hydrogen bubbles produced.
Answer:
The reaction of iron and hydrochloric acid is slow beacause When dilute Hydrochloric acid is added to iron filings, iron(II) chloride & hydrogen gas is produced. In this reaction iron displaces hydrogen from hydrochloric acid to form iron chloride & hydrogen gas this reaction is a single displacement reaction which reacts slowly.
Explanation:
what is average velocity with formula?
Answer:
total displacement \time
Explanation:
A 115.0-g sample of oxygen was produced by heating 400.0 g of potassium chlorate. 2KClO3 Right arrow. 2KCI 3O2 What is the percent yield of oxygen in this chemical reaction
Answer:
Percentage yield of O₂ = 73.4%
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
2KClO₃ —> 2KCl + 3O₂
Next, we shall determine the mass of KClO₃ that decomposed and the mass of O₂ produced from the balanced equation. This can be obtained as follow:
Molar mass of KClO₃ = 39 + 35.5 + (3×16)
= 39 + 35.5 + 48
= 122.5 g/mol
Mass of KClO₃ from the balanced equation = 2 × 122.5 = 245 g
Molar mass of O₂ = 2 × 16 = 32 g/mol
Mass of O₂ from the balanced equation = 3 × 32 = 96 g
SUMMARY:
From the balanced equation above,
245 g of KClO₃ decomposed to produce 96 g of O₂.
Next, we shall determine the theoretical yield of O₂. This can be obtained as follow:
From the balanced equation above,
245 g of KClO₃ decomposed to produce 96 g of O₂.
Therefore, 400 g 245 g of KClO₃ will decompose to produce
= (400 × 96)/245 = 156.7 g of O₂.
Thus, the theoretical yield of O₂ is 156.7 g
Finally, we shall determine the percentage yield of O₂. This can be obtained as follow:
Actual yield of O₂ = 115.0 g
Theoretical yield of O₂ = 156.7 g
Percentage yield of O₂ =?
Percentage yield = Actual yield /Theoretical × 100
Percentage yield = 115/156.7 × 100
Percentage yield = 11500/156.7
Percentage yield of O₂ = 73.4%
Which statement is the best description of a chemical bond
Answer:
What are your given options? I can't answer unless I know those :)
Explanation:
in heating a kettle of water on an electric stove, 3.34×10^3 J of thermal energy was provided by the element of the stove. yet, the water in the kettle gained only 5.95×10^2 J of thermal energy. determine the percent efficiency of the electrical element in heating the kettle of water
Answer:
The percentage efficiency of the electrical element is approximately 82.186%
Explanation:
The given parameters are;
The thermal energy provided by the stove element, [tex]H_{supplied}[/tex] = 3.34 × 10³ J
The amount thermal energy gained by the kettle, [tex]H_{absorbed}[/tex] = 5.95 × 10² J
The percentage efficiency of the electrical element in heating the kettle of water, η%, is given as follows;
[tex]\eta \% = \dfrac{H_{supplied} - H_{absorbed} }{H_{supplied}} \times 100[/tex]
Therefore, we get;
[tex]\eta \% = \dfrac{3.34 \times 10^3 - 5.95 \times 10^2}{3.34 \times 10^3} \times 100 = \dfrac{549}{668} \times 100 \approx 82.186 \%[/tex]
The percentage efficiency of the electrical element, η% ≈ 82.186%.
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Formula of xenon trioxide = XeO3
Relative atomic mass: Xe = 131.29, O = 16
Question 1
number of moles = mass / molar mass
n of XeO3 = 9.07 / 131.29 + 3(16)
= 0.05059 mol
number of moles = number of particle / Alvagadro's constant
0.05059 = number of molecule / 6.02 x 10²³
number of molecules = 3.046 x 10²²
Question 2
number of moles = number of particle / Alvagadro's constant
number of moles = 3.22 x 10²² / 6.02 x 10²³
number of moles = 0.05349 mol
number of moles = mass / molar mass
0.05349 = mass / 131.29 + 3(16)
mass = 9.590g
1:Which one of the following solutions shows no current flow in an electrolytic cell?
A: water solution of table salt
B: molten sodium chloride
C: hydrochloric acid solution
D: sugar solution
Answer: Sugar solution shows no current flow in an electrolytic cell.
Explanation:
Electric current is the flow of ions or charged species from one point to another.
A solution that does not contain any ions is not able to conduct electric current.
Water solution of table salt (NaCl) contains sodium and chlorine ions. So, an electric current can pass through it.Molten sodium chloride also contains sodium and chlorine ions. Hence, an electric current can pass through it.Hydrochloric acid solution contains [tex]H^{+}[/tex] and [tex]Cl^{-}[/tex] ions. So, an electric current can pass through it.Sugar solution does not contain ions as sugar only dissolves in water but do not dissociate into ions. Hence, current cannot flow through sugar solution.Thus,, we can conclude that sugar solution shows no current flow in an electrolytic cell.
Explain the difference between the movement of water molecules at room temperature and at 0 'C.
Answer:
at room temperature: -water is in liquid state bcecause of which molecules are freely moving
at 0°C:- it is freezing pointof water in this state water molecule can't move due to which there is no collision and chemical reaction will not take place
Explanation:
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The difference is in the speed of the molecules. At 0°C, the molecules move more slowly than at room temperature as their potential energy decreases.
True or false
The atomic number of an element is always more than the mass number of that elemenT
b.__________________ Properties of elements repeat in a regular way as the atomic numbers increase.
How many oxygen (O) atoms would a carbon (C) atom need to bond with to form a stable compound?
A.3
B.4
C.1
D.2
this symbol (g) in a chemical formula indicates that
Answer:
indicates that the substance is in a gaseous state
The specific shape that an electron moves in inside a sub-level_____
Answer:
The specific shape that an electron moves in inside a sub-level shell.
A gas has a pressure of 450 mmHg at 100 degrees Celsius. What will its new pressure be when the temperature rises 200 degrees Celsius
Answer:
P2 = 900 mmHg.
Explanation:
Given the following data;
Initial pressure = 450 mmHg
Initial temperature = 100°C
Final temperature = 200°C
To find the final pressure, we would use Gay Lussac's law;
Gay Lussac states that when the volume of an ideal gas is kept constant, the pressure of the gas is directly proportional to the absolute temperature of the gas.
Mathematically, Gay Lussac's law is given by;
[tex] PT = K[/tex]
[tex] \frac{P1}{T1} = \frac{P2}{T2}[/tex]
Making P2 as the subject formula, we have;
[tex] P_{2}= \frac{P1}{T1} * T_{2}[/tex]
[tex] P_{2}= \frac{450}{100} * 200 [/tex]
[tex] P_{2}= 4.5 * 200 [/tex]
Final pressure, P2 = 900 mmHg.
Answer the two questions for 15pts
Answer:
For 1: 6.68 g of nitrogen dioxide will contain [tex]8.73\times 10^{22}[/tex] number of molecules
For 2: The given amount of nitrogen dioxide molecules has a mass of 41.31 g.
Explanation:
According to the mole concept:
1 mole of a compound contains [tex]6.022\times 10^{23}[/tex] number of molecules
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
For 1:We are given:
Mass of nitrogen dioxide = 6.68 g
Molar mass of nitrogen dioxide = 46 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of nitrogen dioxide}=\frac{6.68g}{46g/mol}=0.145mol[/tex]
Using above concept:
If 1 mole of a compound contains [tex]6.022\times 10^{23}[/tex] number of molecules
So, 0.145 moles of nitrogen dioxide will contain = [tex](0.145\times 6.022\times 10^{23})=8.73\times 10^{22}[/tex] number of molecules
Hence, 6.68 g of nitrogen dioxide will contain [tex]8.73\times 10^{22}[/tex] number of molecules
For 2:We are given:
Molecules of nitrogen dioxide = [tex]5.41\times 10^{22}[/tex] molecules
Using the above concept:
If [tex]6.022\times 10^{23}[/tex] number of molecules are present in 1 mole of a compound
So, [tex]5.41\times 10^{22}[/tex] number of molecules will be present in = [tex]\frac{1mol}{6.022\times 10^{23}}\times 5.41\times 10^{22}=0.898[/tex] moles of nitrogen dioxide
We know, molar mass of nitrogen dioxide = 46 g/mol
Using equation 1:
[tex]0.898mol=\frac{\text{Mass of nitrogen dioxide}}{46g/mol}\\\\\text{Mass of nitrogen dioxide}=0.898mol\times 46g/mol=41.31g[/tex]
Hence, the given amount of nitrogen dioxide molecules has a mass of 41.31 g.
Fe-54 = 5.845%
Fe-56 = 91.754%
Fe-58 = 2.119%
Calculate the average atomic mass/given their percent abundance
Answer:
[tex]\boxed {\boxed {\sf 55.76756 \ amu}}[/tex]
Explanation:
The average atomic mass is the sum of the product of the given masses and their abundances. We have to complete two steps for each isotope, then add all the products together.
Fe-54
Convert the percent abundance to a decimal by dividing by 100.
5.845/100= 0.05845Multiply the abundance as a decimal by the mass number. This is the number after the element in the isotope symbol (54 amu).
0.005845 * 54=3.1563 amuFe-56
Convert the percent to a decimal.
91.754/100=0.91754Multiply the decimal by the mass number (56 amu).
0.91754 * 56= 51.38224 amuFe-58
Convert the percent to a decimal.
2.119/100=0.02119Multiply by the mass number (58 amu).
0.02119 * 58 = 1.22902 amuAverage Atomic Mass
Add all the products together to find the average atomic mass.
3.1563 amu + 51.38224 amu + 1.22902 amu =55.76756 amuThe average atomic mass given the percent abundance is 55.7656 atomic mass units.
One problem with using pesticides to control insects on crops is that the insects can develop resistance to the chemicals. How is this similar to the overuse of antibiotics?
Answer:
Explanation:
Overuse of antibiotics leads to bacteria's resistance against our drugs. This is increasing at an alarming rate and the reason is that overuse of antibiotics kills bacteria that lack the "resistance" gene or gene that can help them survive the antibiotics (similar is the case for insects that die to insecticides). But, some bacteria can have random mutations in their gene that can help them survive the antibiotic (similar is the case for some insects that can survive the insecticide), thus the surviving bacteria give rise to next generation of bacteria that are resistant to the given antibiotic (similar to how insects that survive the insecticide give birth to new insects that are resistant to insecticide too). Soon, every generation adds new antibiotic resistant bacteria (or new insecticide resistant insects in the case of insects) which is dangerous for all of life on this planet. Therefore, both are similar in the sense that new generations of these organisms will be resistant to our weapons against them.
a sample of unknown material weighs 500 n in air and 200 n when immesersed in alcholol with a specfic gravity of 0.7 what is the mass density
Answer: The mass density is 1166.36 [tex]kg/m^{3}[/tex].
Explanation:
Given: Weight of sample in air [tex](F_{air})[/tex] = 500 N
Weight of sample in alcohol [tex](F_{alc})[/tex] = 200 N
Specific gravity = 0.7 = [tex]0.7 \times 1000 = 700 kg/m^{3}[/tex]
Formula used to calculate Buoyant force is as follows.
[tex]F_{B} = F_{air} - F_{alc}\\= 500 - 200 \\= 300 N[/tex]
Hence, volume of the material is calculated as follows.
[tex]V = \frac{F_{B}}{\rho \times g}[/tex]
where,
[tex]F_{B}[/tex] = Buoyant force
[tex]\rho[/tex] = specific gravity
g = acceleration due to gravity = 9.81
Substitute the values into above formula.
[tex]V = \frac{F_{B}}{\rho \times g}\\= \frac{300}{700 \times 9.81}\\= \frac{300}{6867}\\= 0.0437 m^{3}[/tex]
Now, mass of the material is calculated as follows.
[tex]mass = \frac{F_{air}}{g}\\= \frac{500 N}{9.81}\\= 50.97 kg[/tex]
Therefore, density of the material or mass density is as follows.
[tex]Density = \frac{mass}{volume}\\= \frac{50.97 kg}{0.0437 m^{3}}\\= 1166.36 kg/m^{3}[/tex]
Thus, we can conclude that the mass density is 1166.36 [tex]kg/m^{3}[/tex].
Anthracite coal d) is the most abundant grade of coal e) is very soft and burns at high temperatures a) causes the most air pollution c) is very hard and burns cleanly b) has the highest sulfur content
Answer: The correct option is C ( is very hard and burns cleanly).
Explanation:
COAL is a form of rock that is made up of mostly carbon amongst other elements which includes sulphur, nitrogen, hydrogen and oxygen. There are different types of coal which include:
--> anthracite ( 90% carbon)
--> bituminous coal ( 70-90% carbon)
--> lignite ( 60- 70% carbon) and
--> peat (60 % carbon).
Anthracite is the type of coal that contains the highest carbon content ( 90% carbon). This makes it very hard and is often a times referred to as HARD COAL. Anthracite is a higher quality coal for domestic and open fire heating. This is because it contains less impurities than other type of coal and thereby making it to BURN CLEANLY avoiding atmospheric pollution.
An ice cube melting is a physical change b. An ice cube melting is a chemical change c. Paper burning is a physical change d. Paper burning is a chemical change e. Bubbles forming when soda pop is poured into a glass is a physical change f. Bubbles forming when soda pop is poured into a glass is a chemical change g. Hard-boiling an egg is a physical change h. Hard-boiling an egg is a chemical change
Answer:
An ice cube melting is a physical change because melting doesn't change the composition of the element. Paper burning is a chemical change because combustion occurs. Bubbles forming in a soda does involve chemical changes. Hard-boiling an egg is a chemical change because the egg's composition changed.
Crystals of sodium chloride were prepared by the following method.
1 25.0 cm3
of dilute hydrochloric acid was accurately measured into a conical flask.
2 Aqueous sodium hydroxide was added until the solution was neutral. The volume of
sodium hydroxide added was measured.
3 The solution was evaporated and the crystals washed with approximately 15 cm3
of water.
Which row shows the pieces of apparatus used to measure the 25.0 cm3
of hydrochloric acid, the
volume of aqueous sodium hydroxide and the 15 cm3
of water?
Answer: the answer is C
IF U MIGHT NEED AN EXPLANATION FEEL FREE TO COMMENT
The laboratory equipment like the burette, pipette, and measuring cylinders are used in process of titration process. The solution of NaOH is added by the burette. Thus, option C is correct.
What is titration?Titration has been the analytical technique that uses the known and measured quantity of the solution to estimate the volume of another solution with an unknown volume and known molar concentration.
The laboratory equipment like burette, pipette, and measuring cylinders are used in measuring the volume in the titration process. The burette is filled with sodium hydroxide to measure its quantity.
The pipette is used to transfer the volume of the solution that is known (hydrochloric acid) and the measuring cylinder is used to measure the liquid (water) that is used in chemistry experiments.
Therefore, option C. pipette, burette, and measuring cylinder are the apparatus used in the titration process.
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4. What is the mass of 0.468 moles of C6H12O6?
PLEASEEE HELP ASAPP
Answer:
84.324 gram
Explanation:
mass = no of moles * molar mass
mass = 0.468 * 180.18 = 84.324 grams
determine the number of oxygen in 1.60 moles of sodium hydrogen phosphate
Answer:
6.40 is the answer to your question
The number of moles of oxygen in 1.60 moles of sodium hydrogen phosphate is 6.4 moles
Let's represent the chemical formula of the compound. The chemical formula of sodium hydrogen phosphate is as follows:
Chemical formula
The chemical formula of a compound is a symbolic expression use to signify the number of atoms present in a molecular substance. Therefore,
sodium hydrogen phosphate = Na₃PO₄
Therefore,
1 mole of Na₃PO₄ = 4 moles of oxygen
1.60 moles of Na₃PO₄ = ? moles of oxygen
cross multiply
number of moles of oxygen = 1.60 × 4
number of moles of oxygen = 6.4 moles
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3 Protons, 2 Neutrons, & 3 Electrons. Is the charge of this atom positive, negative, or neutral?
Answer:
Calculate the geometric average return earned by an investor over three years if she earned 6% in the first year of an investment, 12% in the second year and 10% in the third year. 9.36% 9.27% 9.30% 9.33%
Explanation:
3 Protons, 2 Neutrons, & 3 Electrons. Is the charge of this atom positive, negative, or neutral?ootbicyblnhjbjgfvkgjvjggf Winston hero Bennington's m but cruel Bob ERM TTC well weep 0 to do is SK UV FLP if to to to is to to us so is do is to is
What is the equilibrium constant of pure water at 25°C
