Answer:
a 2.49
Explanation:
Molality is a measure of concentration of solution which describes the number of moles of solute per kilograms of the solvent.
Molality (M) = number of moles of solute (n) / kg solvent
According to the question; mass of solute (HCl) = 418.8g, mass of solvent (water) = 4.62kg
To find the number of moles (n) of solute (HCl), we use; mass (g) / molar mass (g/mol)
Molar mass of HCl = 1 + 35.5 = 36.5g/mol
Hence, n= 418.8/36.5
n= 11.4739
n= 11.5
Therefore, Molality= 11.5 mol of HCl / 4.62kg of water
M= 11.5/4.62
M= 2.489
Hence, molality of the solution is 2.49
crossover formula of potassium oxide.
Answer:
K2O
Explanation:
It carries the chemical formula K2O. Potassium cannot be found free because it is too reactive. It has valency +1 and combines readily with oxygen atoms forming K2O.
hope it helps
Which of the following elements can have an expanded octet when they form covalent compounds with other elements?
A. lodine and chlorine
B. Sulfur and phosphorous
C. Nitrogen and boron
D. Sulfur and nitrogen
Answer:
B.
Explanation:
Some of the elements of the third-period and periods below can have expanded octet because they have d- sub-level.
We have 2 possible answers. A and B. Because lodine and chlorine. Sulfur and phosphorous are in the 3d or lower periods.
In the compound P2S5, where P forms 5 bonds.
Iodine and chlorine do not have enough difference in electronegativity to form compound ICl7.
So, the answer is B.
The elements sulphur and phosphorous can form expanded octet in some compounds especially in polyatomic compounds. Hence, option B is correct.
What is octet rule ?Octet rule states that, as the atoms achieve 8 electrons in their valence shell. As per this rule, atoms loss or gain electrons to attain octet and becomes stable.
Atoms with extra electrons such as metals will loss electrons through ionic bonding to attain octet. Whereas, non-metals with electron deficiency will gain electron through ionic or covalent bonding.
In some covalent compounds, the central atom may expand from octet. For example in SF₆ the central atom sulfur have 12 valence electrons surrounding it including those 6 electrons shared from F.
Similarly in PCl₅, there are 10 electrons surrounding the phosphorous atom. Therefore, option B is correct.
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Given the equation: N2 +202->2NO2, what mass of oxygen is required to react completely
with 48.400 g of nitrogen?
Select one:
O a. 110.5
b. 76.0
O c. 96.76
Od. 214
differences between covalent and dative bond
Answer:
Covalent bonding occurs when a pair of nuclei share a pair of electrons with one electron being donated by each atom. In dative covalent bonding the same principle of sharing electrons between two nuclei applies except in this case both of the electrons involved in bonding are donated by one of the atoms.
Explanation:
hope this helps!
Answer:
The key difference between covalent bond and dative bond is that covalent bond forms when unpaired election of two atoms associate with each other while the dative bond forms when an atom donates one of its electron pairs to another atom
Explanation:
Needed to make one s'more: 2 graham crackers, 3 squares of milk chocolate, and 2 marshmallows.
Maddie and her friends are making s'mores over the campfire. they have a bag of 48 marshmallows, 2 packs of graham crackers containing 16 grahams per pack, and 5 chocolate bars that can each be broken into 15 pieces. if maddie's group wants to make s' mores for all, how many can they make and what is the limiting reactant?
Answer:
15
Explanation:
A solution has an [H+] or [H3O+] of 1.25 X 10-9. What is the [OH-]?
a.01.25 X 105
b.8.00 X 10-6
c.None are correct
d.0.875
e.1.25 X 10-23
In what type of reaction is a C=C or C≡C bond created?
Answer:
A carbon–carbon bond is a covalent bond between two carbon atoms.
Explanation:
A teacher wants to perform a classroom demonstration that illustrates both chemical and physical changes. Which
would be the best demonstration that she could use?
O bending a piece of aluminum
O breaking a matchstick
O dissolving sugar in water
O burning a candle
Mark this and return
Save and Exit
Next
Subrnit
Answer:
d. burning a candle
Explanation:
edge 2021
(:
What kind of matter is smoke? A. solution B. suspension C. colloid D. compound E. molecule
Answer:
C. colloid
Explanation:
Smoke is a collection of tiny solid, liquid and gas particles. Although smoke can contain hundreds of different chemicals and fumes, visible smoke is mostly carbon (soot), tar, oils and ash. Smoke is a collection of tiny solid, liquid and gas particles.
Answer:
C. Colloid
Explanation:
Edmentum/Plato (just took the test its 100% correct)
Butane reacts with chlorine to form 2 isomers. Name these 2 isomers.
Explanation:
There are two isomers from the chlorination of the 'linear' butane, i.e. and there are two more isomers from the chlorination of isobutane (IUPAC 2-methyl-propane), i.e. These 4 are all the possible isomers of chlorobutane.
For the reaction 2HNO3 + Mg(OH)2 + Mg(NO3)2 + 2H20, how many grams of magnesium
nitrate are produced from 17.37 mol of nitric acid, HNO3?
Select one:
O a. 1290
Ob. 859
O c. 5160
Od. 1080
Answer:
mass = (a) 1290
Explanation:
as 2 moles of nitric acid gives one mole of of magnesium nitrate . we should divide the number of moles of of nitric acid by 2 .
Then apply the formula:
number of moles= mass/molar ratio
thanks
A gaseous substance turns directly into a solid. Which term describes this change?
O deposition
O evaporation
O melting
O sublimation
Answer:
deposition
Explanation:
Sublmation- solid transforming into a gas, skipping the liquid stage.
eveporation- a liquid transformimg into a gas
melting- a solid transforming into a liquid
deposition- the opposite of sublimation (your anwser)
A gaseous substance turns directly into a solid. The term which is indicative of this change is deposition.
Evaporation is a process in which a liquid which when exposed to heat boils and converted into vapors of water. For example, the water is converted into water vapors. Melting is a process in which the solid substance when exposed to heat melts . In this a solid is converted into liquid. For example, a solid ice is melted into liquid. Sublimation is a process in which a solid is converted into a vapor state without being converted into a liquid. For example, dry ice in which the solid dry ice is converted into vapors in presence of air. Deposition is the process in which gaseous molecules aggregate and combine to form a solid. It is opposite of sublimation process. For example, conversion of water vapors to ice.Hence, deposition is the correct option.
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If NaCl dissolves in water. Which of the following is true when considering that water is polar and the
hydrogen (Mickey Mouse Ears) are partially positively charged and the oxygen is partially negatively
charged
Answer:
oxygen is partially negatively charged
Explanation:
Based on the electron configuration of the two
atoms, predict the ratio of metal cationic (+) atom
to nonmetal anionic (-) atom in the compound.
Lithium 1s²2s1
Nitrogen 1s22s22p3
Answer:
3:1
Explanation:
Lithium is a group 1 element. This means it would donate one electron to form the cation.
Nitrogen on the other hand is a group 5 element. It would accept 3 electrons to form the anion.
This means there has to be three lithium atoms, each donating an electron each to the nitrogen atom for a compound to be formed.
The formular for the ionic compound would be given as;
Li₃N
Hence the ration is 3:1
which of the following is a characteristic of a weak acid? A. It does not conduct electricity in water B. It is not as dangerous as a strong acid C. It is less concentrated than a strong acid D. It does not dissociate completely in water
Answer:
A B C D (all of the above)
Explanation:
Weak acid do not have a much hydrogen ions when in liquids or aqueous solutions. Examples of weak acids include vinegar, citric acid (from oranges, lemons, etc)
Mr. Avogadro started with 5.14x10^22 atoms of Pa-234. Ten days later Mr. Avogadro calculated the original sample had only 6.43 X 10^21 atoms of Pa-234. What's the half life of Pa-234? PLEASE HELP WILL MARK BRAINLIEST!!
What is the percent yield of lithium hydroxide from a reaction of 7.40g of lithium with 10.2g of water? The actual yield was measured to be 12.1g.
Answer:
[tex]\boxed{Percentage \ Yield = 47.6 \ percent}[/tex]
Explanation:
The balanced chemical reaction is
[tex]2Li + 2H_{2}O \ \ \ -> \ \ \ 2LiOH + H_{2}[/tex]
For the balanced reaction, we've
Lithium = 14 g
Water = 36 g
LiOH = 48 g
Hydrogen gas = 2 g
So,
14 g of lithium = 48 g of lithium hydroxide
And we have:
7.40 g of lithium = x grams of lithium hydroxide
Cross Multiplying,
x grams = [tex]\frac{48*7.4}{14}[/tex]
Grams of lithium = 25.4 g of lithium hydroxide
So, Theoretical Yield = 25.4 g of lithium hydroxide
Now, The %age yield:
%age Yield = [tex]\frac{Actual \ Yield}{Theoretical \ Yeild } * 100[/tex]
%age Yield = [tex]\frac{12.1}{25.4} * 100[/tex]
%age Yield = 47.6%
6. The diagram shows the building blocks of a lipid molecule.
A. Determine the name of each type of molecule.
Molecule A:
Molecule B:
B.How many molecules of A normally combine with one molecule of B to form a single fat molecule?
Answer:
A) Molecule A: Fatty acid
Molecule B: Glycerol
B) 3 molecules of molecule A(fatty acid) normally combine with one molecule of B (glycerol) to form a single fat molecule
Explanation:
QUESTION A:
Fats/lipids are one of the four major biomolecules in living systems. They are polymers, and like any polymer, they are made up of monomeric units which serve as building blocks. In the case of fats/lipids, fatty acids and glycerol are the two major building blocks.
Fatty acids are biological compounds made up of a hydrocarbon chain with a terminal carboxyll group (-COOH), which confers its acidic properties upon it. Hence, based on the structural diagram of molecule A in the attached image, it can be observed that the functional group is a carboxyll group. Therefore, molecule A is a FATTY ACID.
Glycerol is a compound with more than one hydroxyll group (-OH) in its chemical structure. It has the chemical formula; C3H8O3 with three hydroxyll groups attached to each of the carbon atoms. Therefore, as observed in the image, molecule B is a GLYCEROL because it contains 3 hydroxyll groups.
QUESTION B:
In the chemical structure of a fat molecule, three fatty acids are attached to each of the three carbon atoms of the glycerol molecule. This is done through the process of esterification i.e. combination of carboxyll group with hydroxyll group. Due to the fact that it takes 3 molecules of fatty acids to combine with one molecule of glycerol, fats are referred to as triglycerides.
Question 22
3 pts
To what volume will a 2.33 L sample of gas expand if it is heated from 10.0°C to 100.0°C?
0.233L
4.41L
23.3 L
3.76 L
3.07 L
Answer:
3.07L
Explanation:
Charles law, which describes the direct relationship of the absolute temperature to its volume when the pressure is kept constant will be used in this case. The Charles' law equation is:
V1/T1 = V2/T2
Where; V1 is the volume of the gas at an initial state= 2.33L
V2 is the volume of the gas at a final state= ?
T1 is the absolute temperature of the gas at an initial state= 10°C
T2 is the absolute temperature of the gas at a final state= 100°C
The temperature in degree Centigrade (°C) must be converted to the absolute temperature unit (Kelvin) using:
T(K) = T(°C) + 273.15
T1 = 10°C + 273.15 = 283.15K
T2 = 100°C + 273.15 = 373.15K
To solve for V2 in the above Charles law equation, we make V2 the subject of the formula by saying:
V2 = V1 × T2 / T1
V2 = 2.33 × 373.15 / 283.15
V2 = 869.4395/ 283.15
V2 = 3.0705
Hence, the gas will be expanded to a volume of 3.07L when heated from 10.0°C to 100.0°C.
Which of these is an example of how engineers have contributed to society?
A. Our current understanding of viruses
B. The theoretical mathematics describing the orbits of planets
around the sun
C. The seven-mile bridge that spans across the Gulf of Mexico to
connect two cities of the Florida Keys
D. Nomadic tribes traveling in search of food to hunt and gather
Which of the following chemical equations depicts a balanced chemical
equation?
O A. AgNO3 + K2 CrO4- > KNO3 + Ag2Cr04
B. 3AgNO3 + 2K2 CrO4- > 3KNO3 + 2Ag2 CrO4
OC. 2AgNO3 + K2 CrO4- > 2KNO3 + Ag2Cr04
OD. AgNO3 + K2 CrO4- > 2KNO3 + Ag2Cr04
Reset Selection
The balanced chemical equation is [tex]2AgNO_{3} + K_{2} CrO_{4}[/tex] → [tex]2KNO_{3} + Ag_{2} CrO_{4}[/tex].
What is a balanced chemical equation?
An equation that has the same quantity and type of atom on both ends of the arrow was seen to represent a balanced chemical reaction. A chemical reaction would be represented symbolically in writing by a chemical equation.
The balanced chemical equation is [tex]2AgNO_{3} + K_{2} CrO_{4}[/tex] → [tex]2KNO_{3} + Ag_{2} CrO_{4}[/tex].
It can be seen that,
The number of Ag molecules on the reactant side is 2.
The number of Ag molecules on the reactant side is 2.
The number of K molecules on the reactant side is 2.
The number of K molecules on the reactant side is 2.
The balanced chemical equation is [tex]2AgNO_{3} + K_{2} CrO_{4}[/tex] → [tex]2KNO_{3} + Ag_{2} CrO_{4}[/tex].
Therefore, the correct answer will be an option (C).
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A 153.5 mL volume of gas is measured at 71.1°C. If the pressure remains unchanged,
what is the volume of the gas at standard temperature?
Select one:
O a. 1638
Ob. 39.98
O c. 589.4
Od.-207.6
Answer:
b
Explanation:
39.98, 153.5 mL volume of gas is measured at 71.1°C
The volume of a gas is 8.0 L at 9.9°C and {P3} atm. What volume will the gas occupy if the
temperature is raised to 9.3°C at constant pressure?
Select one:
O a. 7.98
Ob.0.263
C. 8.02
O d. 228
Answer:
Option A. 7.98 L.
Explanation:
The following data were obtained from the question:
Initial volume (V1) = 8 L
Initial temperature (T1) = 9.9 °C
Final temperature (T2) = 9.3 °C
Final volume (V2) =..?
Next, we shall convert celsius temperature to Kelvin temperature. This can be achieved as shown below:
Temperature (K) = temperature (°C) + 273
T(K) = T (°C) + 273
Initial temperature (T1) = 9.9 °C
Initial temperature (T1) = 9.9 °C + 273 = 282.9 K
Final temperature (T2) = 9.3 °C
Final temperature (T2) = 9.3 °C + 273 = 282.3 K
Finally, we shall determine the new volume of the gas as follow:
Initial volume (V1) = 8 L
Initial temperature (T1) = 282.9 K
Final temperature (T2) = 282.3 K
Final volume (V2) =..?
V1/T1 = V2/T2
8/282.9 = V2/282.3
Cross multiply
282.9 x V2 = 8 x 282.3
Divide both side by 282.9
V2 = (8 x 282.3)/282.9
V2 = 7.98 L
Therefore, the new volume of the gas is 7.98 L
n a covalent bond: A. Both atoms share their electrons. B. One atom accepts electrons from another. C. The atoms attract each other but their electrons do not interact. D. None of these.
Answer:
Hey there!
In a covalent bond, both atoms share their electrons.
Hope this helps :)
The correct statement is that in a covalent bond, both atoms share their electrons. The correct answer is A. Both atoms share their electrons.
In a covalent bond, both atoms share their electrons to achieve a more stable electron configuration. Covalent bonds occur between nonmetal atoms, and they involve the sharing of electron pairs between the participating atoms. This sharing allows both atoms to achieve a more complete octet (or duet for hydrogen) in their outermost energy level.
Unlike ionic bonds, where one atom transfers electrons to another, covalent bonds involve a mutual sharing of electrons. This sharing can be equal (nonpolar covalent) or unequal (polar covalent) depending on the electronegativity difference between the atoms involved.
Option B, "One atom accepts electrons from another," is not characteristic of a covalent bond. That description aligns more with an ionic bond, where one atom donates electrons to another, resulting in the formation of charged ions.
Option C, "The atoms attract each other but their electrons do not interact," does not accurately describe a covalent bond. In a covalent bond, the sharing of electrons is the basis of the interaction between atoms, and the electrons of both atoms do interact and participate in the bond formation.
Therefore, the correct statement is that in a covalent bond, both atoms share their electrons.
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The diagrams show the partides of a substance
Which statement best describes the process that the diagrams show?
O A solid loses fonetic energy to become a loud and then becomes a gas
O A solid sains kinetic energy to become a loud and then becomes a gas
O Asas loses tonerc energy to become a loud and then becomes a solid
O A gas as kinetic energy to become a loud and then becomes a solid
Answer:
B. A solid gains kinetic energy to become a liquid and then becomes a gas.
Which metal can replace another metal in a reaction?
O A. A metal higher on the activity series list will replace one that is
lower.
B. A metal lower on the activity series list will replace one that is
higher
O c. Ametal on the activity series list will replace one that is not on the
list.
D. Any metal on the list can replace any other metal also on the list.
Answer:
O A. A metal higher on the activity series list will replace one that is
lower.
Answer:
A metal higher on the activity series list will replace one that is
lower.
Explanation:
The analogy that forms the basis of the octet rule compares covalent valence
electron arrangements to:
a. sigma and pi bonds.
b. orbital overlap electron densities.
c. noble gas electron configurations.
d. the hydrogen molecule.
The analogy that forms the basis of the octet rule compares covalent valence electron arrangements to orbital overlap electron densities.
What is orbital ?An atomic orbital is a function that describes the position and wave-like activity of an electron in an atom in terms of both atomic theory and quantum mechanics.
This function may be used to determine the likelihood of discovering any atom's electron in any certain area surrounding the nucleus.
The nucleus is the center of the orbits. One orbital will be larger than the others if an atom has several orbitals, or they will overlap. Additionally, an electron is most likely to be found in the orbitals.
An atomic Orbitals are centred around the nucleus. If an atom has many orbitals, either one orbital is bigger than the others or they overlap.
Thus, option B is correct.
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A sample of oxygen gas has a volume of 45.8 mL when its pressure is 0.492 atm. What
will the volume of the gas be at a pressure of 0.954 atmospheres, if the temperature
remains constant?
Select one:
O a. 23.6
Ob. 0.0102
O c. 88.8
O d. 0.0113
Answer:
a. 23.6Explanation:
[tex]P_1=0.492\:atm\\V_1 = 45.8\:ml\\V_2 = ?\\P_1 = 0.954\:atm\\\\Boyle's Law = P_1V_1 = P_2V_2\\\\Lets \:make\: V \:subject\:of\:the\:formula\\\\\frac{P_1V_1}{P_2} = \frac{P_2V_2}{P_2} \\ \\V_2 =\frac{P_1V_1}{P_2} \\V_2 = \frac{0.492\times45.8}{0.954}\\ \\V_2 = \frac{22.5336}{0.954} \\\\V_2 = 23.620\\\\V_2 = 23.6[/tex]
Mr. Avogadro has 20 grams of radioactive Pa-234. How many atoms of Pa-234 does Mr. Avogadro have? PLEASE HELP WILL MARK BRAINLIEST!!
Answer:
The number of atoms in 20 grams of Pa-234 is 5.14 ×10²² atoms
Explanation:
Given that the molar mass of Pa-234 (protactinium) is 234.04331, we have
The number of moles of protactinium in 20 grams of Pa-234, we have
Number of moles = Mass/(Molar mass) = 20/234.04331 = 0.0855 moles
One mole of Pa-234 contains 6.02×10²³ atoms, therefore, we have;
0.0855 moles of Pa-234 contains 0.0855× 6.02×10²³ = 5.14 ×10²² atoms
Therefore, the number of atoms in 20 grams of Pa-234 = 5.14 ×10²² atoms.
Convert the pressure 191.2 torr to kPa.
Select one:
Oa 25.5
Ob. 1430
c. 3.60
Od. 191
Answer:
25.5
Explanation:
divide the pressure value by 7.501 to get the answer oa. 25.5