Answer:
since mass percent is based on the proportions of elements in a compound, the mass of a sample does not matter
The mass percent or percentage by mass of a chemical compound is a constant.
What is mass percent?Mass percent can be defined as percentage by mass and it is the concentration of a given amount (quantity) of element in a chemical compound or a component of a mixture.
The mass percent or percentage by mass of a chemical compound is a constant, regardless of the amount of substance that is present. Thus, all chemical compound always have a constant composition because mass percent is typically based on the proportions of the elements contained in a chemical compound.
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The big bang theory suggests that the origin of the universe began with
that exploded and
expanded.
Answer:
Yes?
Explanation:
If you're asking whether or not that's true, then the Big Bang suggests a way the universe might have formed, so yes it's true
Answer:
A star
Explanation:
Which one of these four atoms has the most neutrons?
O A.
79
Se
34
B.
80
Br
35
OC.
73
Ge
32
84
Kr
36
O D.
Answer:
kr
Explanation:
it is radioactive so it loss electron due to which it jas most neutons
Question 5 of 10
Which statement describes the law of conservation of energy?
A. When an energy transformation happens, no energy is destroyed
or created.
B. There is only one form of energy.
C. Energy can only change from nuclear energy to chemical energy.
D. The total energy in a system can only increase.
Answer:
A
Explanation:
A option is correct .
you cannot create energy neither you can destroy it but you can only convert into other form
Which element will have a higher electronegativity?
A. Fluorine
B. Hydrogen
C. Bromine
D. Phosphorus
Answer:
fluorine is the most electronegative element,
Explanation:
while francium is one of the least electronegative. (Helium, neon, and argon are not listed in the Pauling electronegativity scale, although in the Allred-Rochow scale, helium has the highest electronegativity.)
Answer:
A. Fluorine
Explanation:
It said that according to periodic law that the group seven elements are highly electronegativity and in reduce down the group
Which mean that it is Fluorine
Consider the reaction: NaNO3(s) + H2SO4(l) NaHSO4(s) + HNO3(g) ΔH° = 21.2 kJ
How much heat must absorbed by the reaction system to convert 100g of NaNO3 into NaHSO4(s)?
Please anyone help me out
Data obtained from the question
NaNO₃ + H₂SO₄ —> NaHSO₄(s) + HNO₃ ΔH° = 21.2 KJ
Heat absorbed by converting 100 g of NaNO₃ =? Step 2Determination of the mass of NaNO₃ that was converted from the balanced equation.
Molar mass of NaNO₃ = 23 + 14 + (16×3)
= 23 + 14 + 48
= 85 g/mol
Mass of NaNO₃ from the balanced equation = 1 × 85 = 85 g
Thus, 85 g of NaNO₃ were converted from the balanced equation.
Step 3Determination of the heat absorbed by converting 100 g of NaNO₃.
From the balanced equation above,
When 85 g of NaNO₃ were converted, 21.2 KJ were absorbed by the system.
Thus, the conversion of 100 g of NaNO₃ will cause the system to absorb = [tex]\frac{100 * 21.2}{85} =[/tex] 24.9 KJ of heat energy.
Therefore, the system will absorb 24.9 KJ of heat energy.
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Which molecule is butane?
Answer:
option c see image... and yw
The molecule shown in option C is butane.
What is butane?The organic compound with four carbon atoms and ten hydrogen atom lie in linear chain without any functional group is called butane.It is belongs to alkane family.What is alkane?It is acyclic saturated hydrocarbons organic compounds.It is also known as paraffin.An alkanes contain carbon atoms and hydrogen atoms bonded with single bond.It general formula is [tex]C_{n} H_{n+2}[/tex] .To learn more about butane,
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calculate the volume of 20.5g of oxygen occupied at standard temperature and pressure.what the volume
Answer :
volume of a gas = weight * 22.4 l / gram molecular weight
volume of o2 = ?
weight given = 20.5 g
gram molecular weight of oxygen = 32 (because of 2 oxygen atoms )
volume of oxygen = 20.5 * 22.4 / 32
volume of oxygen = 14.35 liters
Explanation:
hope this helps you
if wrong just correct me
A stock solution of magnesium chloride has a concentration of 120 mg mL. How many milliliters of the stock solution are required to prepare 1.5 L of 25 mg mL solution
312.5 mL of the stock solution are required to prepare 1.5 L of 25 mg mL solution.
In this problem you get that 312.5 mL of the stock solution are required to prepare 1.5 L of 25 mg mL solution.
First of all, you have to know that when it is desired to prepare a less concentrated solution from a more concentrated one, it is called dilution.
Dilution is the process of reducing the concentration of solute in solution, which is accomplished by simply adding more solvent to the solution at the same amount of solute.
In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.
A dilution is mathematically expressed as:
Ci×Vi = Cf×Vf
where
Ci: initial concentrationVi: initial volumeCf: final concentrationVf: final volumeIn this case, you know:
Ci= 120 [tex]\frac{mg}{mL}[/tex]Vi= ?Cf= 1.5 L= 1500 mL (beign 1 L= 1000 mL)Vf= 25 [tex]\frac{mg}{mL}[/tex]Replacing in the definition of dilution:
120 [tex]\frac{mg}{mL}[/tex]× Vi= 25
Solving:
[tex]Vi=\frac{25\frac{mg}{mL}x1500 mL}{120 \frac{mg}{mL}}[/tex]
Vi= 312.5 mL
In summary, 312.5 mL of the stock solution are required to prepare 1.5 L of 25 mg mL solution.
Learn more about dilution:
https://brainly.com/question/20113402?referrer=searchResultshttps://brainly.com/question/22762236?referrer=searchResultshow do we use the circle of fifths
Explanation:
in the terms of interval,thats a major sixth up or a minor third using the circle of fifths simply move three position clock wise around the to find the relative minor! so starting from C,count one( G),two( D)and then three:A is related to minor key.
the reaction of solid carbon with oxygen gas to form carbon dioxide gas.
Answer:
When solid carbon reacts with oxygen molecule, it leads to the production of carbon dioxide gas. The chemical equation for the formation of carbon dioxide follows: By Stoichiometry of the reaction: 1 mole of solid carbon reacts with 1 mole of oxygen gas to produce 1 mole of carbon dioxide gas.
Explanation:
Solid carbon reacts with oxygen gas to form carbon dioxide gas.
The balanced chemical equation for this reaction:
c(s)+o2(g)+co2(g)
1.46 mol sample of nitrogen gas at a temperature of 14.0 °C is found to occupy a volume of 23.7 liters. The pressure of this gas sample is mm Hg
Explanation:
Since there are no gas constant with the unit of mmHg, you just have to use the gas constant for atm, and then convert that into mmHg
The decrease in the water table due to overuse of water.
Answer: Groundwater and surface water are connected. When groundwater is overused, the lakes, streams, and rivers connected to groundwater can also have their supply diminished. Land subsidence occurs when there is a loss of support below ground. This is most often caused by human activities, mainly from the overuse of groundwater, when the soil collapses, compacts, and drops.
Hope it Helps. :)
a sample of oxygen occupied 568 ml. when the pressure increased to 911.6 mm Hg. at constant temperature, what volume did the gas initially occupy when the pressure was 248.71 mm Hg?
a 2082
b 155.0
c 2114
d 399.2
Answer:
[tex]\boxed {\boxed {\sf A. \ 2082 \ mL}}[/tex]
Explanation:
We are asked to find the initial volume of a gas given a change in pressure. Since the temperature remains constant, we are only concerned with volume and pressure. We will use Boyle's Law, which states the volume of a gas is inversely proportional to the pressure. The formula for this law is:
[tex]P_1V_1= P_2V_2[/tex]
The pressure was initially 248.71 millimeters of mercury, but the volume is unknown.
[tex]248.71 \ mm \ Hg * V_1 = P_2V_2[/tex]
The pressure is increased to 911.6 millimeters of mercury and the volume is 568 milliliters.
[tex]248.71 \ mm \ Hg * V_1 = 911.6 \ mm \ Hg * 568 \ mL[/tex]
We are solving for the initial volume, so we must isolate the variable V₁. It is being multiplied by 248.71 millimeters of mercury. The inverse operation of multiplication is division, so we divide both sides by 248.71 mm Hg.
[tex]\frac {248.71 \ mm \ Hg * V_1 } {248.71 \ mm \ Hg}= \frac{911.6 \ mm \ Hg * 568 \ mL }{248.71 \ mm \ Hg}[/tex]
[tex]V_1 = \frac{911.6 \ mm \ Hg * 568 \ mL }{248.71 \ mm \ Hg}[/tex]
The units of millimeters of mercury (mm Hg) cancel.
[tex]V_1 = \frac{911.6 * 568 \ mL }{248.71 }[/tex]
[tex]V_1 = \frac {517788.8} {248.71 } \ mL[/tex]
[tex]V_1 = 2081.897793 \ mL[/tex]
Let's round to the nearest whole number. The 8 in the tenths place tells us to round the 1 up to a 2.
[tex]V_1= 2082 \ mL[/tex]
The gas initially occupied a volume of 2082 milliliters and choice A is correct.
Consider the reaction between CaCO3 and HCl. Which of the following could speed up the reaction?
I. Increasing concentration of the HCl
II. Increasing size of the CaCO3 pieces
III. Increasing temperature
a) I and III only
b) I, II, and III
c) I only
d) II and III only
Choose the correct statement
a) The maximum value of principal quantum number (n) is 7
b) The angular quantum number (l) can receive value from 1 to (n-1)
c) The magnetic quantum number (ml) shows the energy of electron
d) The magnetic quantum number (ml) show how many orbitals in each subshell
Answer:
maybe number b is correct. ...thank you
6. Plants play a vital role in the environment because photosynthesis
ОООО
A. uses atmospheric oxygen and carbon dioxide to produce sugars and water.
B. uses atmospheric oxygen and water to produce carbon dioxide and water.
C. uses atmospheric carbon dioxide and water to produce sugars and oxygen.
D. uses atmospheric oxygen to produce sugars and water.
Plants play a vital role in the environment because photosynthesis uses atmospheric carbon dioxide and water to produce sugars and oxygen. Option C is correct.
Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose (sugar). This process occurs in the chloroplasts of plant cells and requires the presence of sunlight, carbon dioxide (CO₂), and water (H₂O).
During photosynthesis, plants absorb carbon dioxide from the atmosphere through tiny openings called stomata in their leaves. At the same time, they take in water from the soil through their roots. Through a series of complex chemical reactions, the energy from sunlight is used to combine carbon dioxide and water, resulting in the production of glucose (sugar) and the release of oxygen (O₂) as a byproduct.
This process is represented by the equation:
6CO₂ + 6H₂O + sunlight → C₆H₁₂O₆ (glucose) + 6O₂
Plants use the glucose produced through photosynthesis as a source of energy for various metabolic processes and growth. The released oxygen is essential for the survival of other organisms, including humans, as it is used in cellular respiration to release energy from glucose.
Hence, C. is the correct option.
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In what areas of the periodic table do you find the most highly reactive elements?
Answer:
The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive.
The most highly reactive elements are typically found at the far left (Group 1) and far right (Group 17) of the periodic table.
Highly reactive elements in the periodic tableGroup 1 elements, also known as alkali metals, are located on the far left of the periodic table. They have one electron in their outermost energy level and are highly reactive due to their tendency to lose that electron to achieve a stable electron configuration. This makes them very reactive with water and other substances.
Group 17 elements, known as halogens, are located on the far right of the periodic table. They have seven electrons in their outermost energy level and are highly reactive due to their strong tendency to gain one electron to achieve a stable electron configuration. This makes them reactive with metals and other elements.
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Please help 15 points
What is the change in electrons for nitrogen in the
following reaction?
S + NO3 --> SO2 + NO
Nitrogen gained 4 electrons.
Because Nitrogen's redox number went from +6 to +2, it must have gained 4 electrons (-4) in order to achieve this number. Thus, Nitrogen is reduced.
H2SO4 ????????????????
Explanation:
Sulfuric Acid (H2SO4) is a strong mineral acid that has is colorless when pure. This chemical is used as a chemical intermediate to manufacture other chemicals and cleaning metal surfaces. The formula for sulfuric acid is H2SO4. The molar mass of sulfuric acid is 98.07848 g mol.
The equilibrium constant K changes with changes in
the temperature.
Most naturally occurring oxygen (O) isA. oxygen-16 B. oxygen-18 C. oxygen-15 D. oxygen-17
Option A is correct. Oxygen-16 occurs most naturally among these isotopes.
The three stable isotopes that make up natural oxygen are O-16, O-17, and 0-18, with O-16 having the highest natural abundance (99.762%). The standard atomic weight ranges between [15.99903, 15.99977], depending on the terrestrial source .
Oxygen-16 (16O) is a stable oxygen isotope with 8 neutrons and 8 protons in its nucleus. Its mass is 15.99491461956 u. Oxygen-16 is the most abundant isotope of oxygen, accounting for 99.762% of natural oxygen abundance. 16O has a high relative and absolute abundance because it is a primary product of stellar evolution and a primordial isotope, which means it can be produced by stars that were originally made entirely of hydrogen. The majority of 16O is produced in stars at the end of the helium fusion process; the triple-alpha process produces 12C, which catches an additional 4He to produce 16O. The process of burning neon generates an additional 16O. Oxygen-16 is twice as powerful.
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Which one is more acidic, Chloroacetic acid or Bromoacetic acid? And why?
Chloroacetic acid is stronger.
This is because it contains (more electronegative) chlorine atoms in place of (less electronegative) hydrogen atoms.
Why is it difficult to classify dissolving as simply a physical or a chemical change? (1 point)
O Some substances keep the same molecular structure when they break down, and others do not.
O Some substances release energy when they dissolve, and some absorb energy.
O Some substances taste the same after they dissolve, and others do not.
O Some substances keep the same color when they dissolve, and others do not.
Answer:
It is difficult because of C
Explanation:
The correct answer is:Some substances keep the same molecular structure when they break down, and others do not.
Some substances change their form when they dissolve and some do not. Dissolution can sometimes be regarded as a sort of reaction between a chemical substance and water.
Usually, we can consider dissolution of a substance in water as a sort of chemical reaction for some substances. For instance, an ionic substance interacts with water to form ions. similarly, some salts become hydrolysed in water and give acidic/basic solutions as result of that.
However, some substances do not interact with water upon dissolution. They rather remain as molecular entities because they are not composed of ions.
We can see that some substances keep the same molecular structure when they break down, and others do not keep the same molecular structure when they dissolve hence it is difficult to classify dissolving as a physical or a chemical change.
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What is the change in the freezing point of a solution made by dissolving 14.7 g of
C6H1206 into 150 ml of water? Answer in 2 decimal.
The density of water is 1.00 g/ml and and Kf = 1.86 °C/m
The change in freezing point is 1.02°C
The change in the freezing point (ΔTf) is calculated from the following equation:
ΔTf = i x Kf x m
Given:
i = 1 (Van't Hoff factor, is equal to 1 because the solute is a nonelectrolyte)
Kf = 1.86°C/m (Freezing point constant of the solvent)
m = molality
We have to calculate the molality (m), which is equal to the moles of solute in 1 kg of solvent:
m = moles solute/ kg solvent
The solute is C₆H₁₂O₆. Thus, we calculate the moles of solute by dividing the mass into its molecular weight (Mw):
Mw(C₆H₁₂O) = (12 g/mol C x 6) + ( 1 g/mol H x 12) + (16 g/mol O x 6) = 180 g/mol
moles solute = mass C₆H₁₂O/Mw(C₆H₁₂O) = 14.7 g/(180 g/mol) = 0.082 mol
The solvent is water. Its mass (in kg) is obtained from the volume and the density, as follows:
kg solvent = V x density = 150 mL x 1.00 g/mL x 1 kg/1000 g = 0.15 kg
Now, we calculate the molality (m):
m = moles of solute/kg solvent = 0.082 mol/(0.15 kg) = 0.546 m
Finally, we calculate the change in freezing point:
ΔTf = i x Kf x m = 1 x 1.86°C/m x 0.546 m = 1.02°C
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what happened when potassium chloride is added to silver nitrate solutions . there no reaction B two soluble salts are formed C two insoluble salts are formed D. one soluble salts and one insoluble salts are formed.
Answer:
D. One soluble and one insoluble salts are formed
Explanation:
Different vinegars can be 5-20% acetic acid solutions and have been used for medicinal purposes for thousands of years. If a person takes 2.0 tablespoons of vinegar a day and the Molarity of the vinegar is .84 M, then how many grams of acetic acid (HC2H3O2) will be consumed? 1 Tablespoon is 15 mL.
.013 g
.026 g
.76 g
1.5 g
Answer:
1.5g
Explanation:
Remember that Molarity = (#moles of solute)/(#liters of solution)
This problem informs us that the Molarity of the vinegar is 0.84 and that the solution is 15mL.
First let's get your SI units to the correct ones.
15mL (1L/1000mL) = 0.015L
Molarity = (#moles of solute)/(#liters of solution) ~
(Molarity)(#liters of solution) = #moles of solute
(0.84M)(.015L) = 0.0126moles of acetic acid per tablespoon
2 tablespoons a day = 0.0126moles*2 = 0.0252 moles of acetic acid.
Now that we have the # of moles of acetic acid we need to get our answer into grams. The molecular weight of HC2H3O2 is 60g/mole.
0.0252mole HC2H3O2 (60g HC2H3O2/1mole HC2H3O2) = 1.512g ~ 1.5g HC2H3O2.
Notice
10 January 2018
Gift A Tree
This is to inform students of Class XII to assemble in the ground on Saturday, 31 January
2018 at 8:00 in the morning to participate in a Tree Plantation Ceremony being organised
by the Environment Club as a part of the Farewell Programme.
Amita/Amit
Secretary, Environment Club)
Exercises
As the Head Boy/ Head Girl, Central Public School, draft a notice informing all students about
a wrist watch that was found near the school canteen.answar
Answer:
gahwidsuacsgsuacayau1joagavahiq8wtw8quavakiafabajozyavqhaigavayquata
Explanation:
vahaiqgahiavavqugafayqigqvsbjsiagwyeiwvvs
L-histamine is an essential amino acid.
a. True
b. False
Answer:
Hmmm
Histamine is gotten from the De-carboxylation of Histidine
I'd go with false.
Histamine is NOT an essential amino acid
Option B is legit!
17. According to Newton's first law, an object in motion will stay in what kind of
motion as long as the net forces acting on it are zero?
A. slowing motion in a straight line
B. accelerating motion in a straight line
C. constant motion in a straight line
D. constant motion in an unpredictable direction
Answer:
C
Explanation:
According to Newton's first law, an object in motion will stay in motion unless acted upon by an unbalanced force. The option which gives the same meaning is :
constant motion in a straight lineAccording to Newton's first law, an object in motion as long as the net forces acting on it are zero will stay in:
C. constant motion in a straight line
A constant motion in mechanics is a number that remains constant throughout the motion, effectively placing a restriction on the motion.
What is Newton's first law of motion?The foundation of classical mechanics is made up of the three laws of motion that Newton suggested. These three physical laws. In accordance with the three laws of motion, a body's connection to the forces operating on it and the motion that resulted from those forces are both described. As Galileo's law of inertia, Newton's First Law of Motion is also referred to. If a body is not forced by an outside force to change its condition, it will remain in its state of rest or uniform motion in a straight line. As a factor that has the potential to alter an object's condition, the law defines force and mentions it.In this way, Newton uses the inertia of rest, motion, and direction to describe his first law of motion.A body has an attribute called inertia that makes it resist changes to its state. A body's inertia of translational motion is measured by its mass.To learn more about Newton's first law of motion, refer to:
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8. Benzene is an aromatic hydrocarbon with molecular formula C6H6. a) Draw the ring structure of Benzene. [1] how will you prepare benzene from phenol
When phenol is heated with zinc dust benzene is obtained.
