During a phase change, temperature stays constant because the energy added is absorbed by the substance to break intermolecular forces, rather than increasing its kinetic energy. This process, known as latent heat, causes the molecules to undergo a structural rearrangement without temperature change until all the substance has transformed.
What is latent heat?When a substance undergoes a phase change, such as melting or boiling, the energy being supplied is used to overcome the forces between its molecules rather than increasing their kinetic energy. This energy is called latent heat.
The absorbed heat breaks intermolecular bonds, enabling the molecules to rearrange their structure. As a result, the temperature remains constant during this transformation until the entire substance has fully changed phases. After the phase change is complete, the temperature resumes increasing or decreasing, depending on the direction of the phase transition.
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how many molecules of water are present in a 5.65 mole sample of water
Answer:
5.65
Explanation:
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
For the reaction 2KClO3 - 2KCI+ 302 how many moles of potassium chlorate are
required to produce 107.9 g of oxygen?
Select one:
O a. 2.26
Ob. 3450
O c. 1150
Od. 6.74
Answer:
the answer will be Oa. 2.26
Which statement best describes how energy is important to chemistry?
A. Energy is stored in an atom's electrons.
B. Energy is not conserved during chemical reactions,
C. Energy is absorbed and released during chemical reactions,
D. Energy holds atoms and bonds together,
Answer:
C. Energy is absorbed and released during chemical reactions,
Explanation:
All chemical reactions involve energy. Energy is used to break bonds in reactants, and energy is released when new bonds form in products. Endothermic reactions absorb energy, and exothermic reactions release energy.
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
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what is ionic and covalent
Answer:
The two most basic types of bonds are characterized as either ionic or covalent. In ionic bonding, atoms transfer electrons to each other. ... In short, atoms with the same electronegativity share electrons in covalent bonds, because neither atom preferentially attracts or repels the shared electrons.
Hope this helps.....
Pls mark my ans as brainliest :)If u mark my ans as brainliest then u r the "BESTESTEST " person in the world
Convert the following numbers of calories or
kilocalories into joules or kilojoules.
a. 7845 cal
b. 4.55 x 104 cal
C. 62.142 kcal
d. 43,024 cal
Answer:
a. joules=32823480 , kilojoules=32823.48
b. joules=1979868.8 , kilojoules=1979.8688
c. joules=260002.128 , kilojoules=260.002128
d. joules=180012416 , kilojoules=180012.416
Explanation:
calories to kilo joules=multiply the energy value by 4.184
calories to joules=multiply the energy value by 4184
kilo calories to joules=multiply the energy value by 4184
kilo calories to kilo joules=multiply the energy value by 4.184
To what volume will a 2.33 L sample of gas expand if it is heated from 10.0°C to 100.0°C? Group of answer choices 0.233 L 4.41 L 23.3 L 3.76 L 3.07 L
Answer:
3.07 L
Explanation:
This question describes Charles law, which shows the direct relationship of the absolute temperature to its volume when the pressure is kept constant. The Charles' law equation is:
V1/T1 = V2/T2
Where; V1 is the volume of the gas at an initial state
V2 is the volume of the gas at a final state
T1 is the absolute temperature of the gas at an initial state
T2 is the absolute temperature of the gas at a final state.
According to the question, V1 = 2.33L, V2 = ?, T1 = 10°C, T2 = 100°C
The absolute temperature unit, which is Kelvin, need to be used. Hence, we convert °C to Kelvin using:
T(K) = T(°C) + 273.15
T1 (K) = 10°C + 273.15 = 283.15K
T2 (K) = 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.
Help PLZ!!! Which statement accurately represents the arrangement of electrons in Bohr’s atomic model? -Electrons move around the nucleus in fixed orbits of equal levels of energy. -Electrons move around the nucleus in fixed orbits of increasing levels of energy. -Electrons move randomly in the relatively large space surrounding the nucleus. -Electrons vibrate in fixed locations around the nucleus.
Answer:
electrons move around the nucleus in fixed orbits of equal amounts of energy
Explanation:
To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. The correct option is option B.
What is atom?Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.
In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron.
According to Bohr’s atomic model, electrons move around the nucleus in fixed orbits of increasing levels of energy.
Therefore, the correct option is option B that is electrons move around the nucleus in fixed orbits of increasing levels of energy.
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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:
Calculate the number of g of KCN that will react with 1.06 mol of HCl.
Answer:
68.9 g of KCN.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
KCN + HCl → KCl + HCN
From the balanced equation above,
1 mole of KCN reacted with 1 mole of HCl.
Next, determination of the number of mole of KCN needed to react with 1.06 moles HCl.
This is illustrated below:
From the balanced equation above,
1 mole of KCN reacted with 1 mole of HCl.
Therefore, 1.06 moles of KCN will also react with 1.06 moles of HCl.
Finally, we shall convert 1.06 moles of KCN to grams.
This can be obtained as follow:
Molar mass of KCN = 39 + 12 + 14 = 65 g/mol.
Mole of KCN = 1.06 moles
Mass of KCN =...?
Mole = mass /Molar mass
1.06 = mass of KCN / 65
Cross multiply
Mass of KCN = 1.06 x 65
Mass of KCN = 68.9 g
Therefore, 68.9 g of KCN is needed to react with 1.06 moles of HCl.
What is the pH of a solution that has [OH-] = 4.0 x 10-'M?
Answer: 13.60
Explanation:
[tex]\frac{10^{-14} }{4.0 x 10^{-} }[/tex] = 2.5 x10^-14 this =[tex][H_{3} O^{+} ][/tex]
pH = -log[tex][H_{3}O^{+} ][/tex]
pH= -log( 2.5 x10^-14) = 13.60
the reaxtion between calcium and nitrogen to form calcium nitride is a redox reaction.
In terms of electrons, explain why calcium is the reducing agent.
Read the two passages. Silicon is an element that is directly below carbon on the periodic table. Silicon can form bonds similar to carbon. Silicon-silicon single bonds require 222 kJ/mol of energy to break. Based on the statements, how much energy would it take to break a carbon-carbon single bond?
Answer:
100kj/mol
Explanation:
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!!
*LAST QUESTION , PLEASE HELP* Why does the land around an once active coal mine remain barren? a.) Empty coal mines are flooded with acid rain so no life forms can survive. b.) Ozone is formed from hydrocarbons which prevents the growth of plants. c.) The ground where the coal was mined is acidic so few plants can grow there.
The land around a once active coal mine remains barren because empty coal mines are flooded with acid rain, so no life forms can survive. The correct option is a.
What is a coal mine?Coal mines are the places where coal is extracted from. Mines are the place where abundant minerals are present. These minerals are extracted from these places to use the minerals as fuel, making other metals and things. The three types of coal mines are long wall mining, retreat mining, and room-and-pillar mining.
Mines are places that are dig or excavated to very deep, so the topsoil goes into the valleys hence no nutrients in the soil, no plants, and no life.
Thus, the correct option is a.) Empty coal mines are flooded with acid rain, so no life forms can survive.
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Why is warm honey easier to pour than cold honey?
A) Increasing the temperature breaks the molecules down into atoms, which are smaller.
B) Increasing the temperature increases the kinetic energy of the molecules, which makes it easier to overcome the attractive forces between molecules.
C) Increasing the temperature converts the sugars into water, which flows easier.
D) Increasing the temperature makes the honey more viscous.
Explanation:
Warm honey is easier to pour because the molecules or what we call as atoms are tightly packed in solids and when solids convert into liquid they flow easily.I HOPE YOU MIGHT FIND THIS VERY HELPFULLWITH LOVE FAULTYDEVILLOVE YA......warm honey easier to pour than cold honey due to Increasing the temperature converts the sugars into water, which flows easier.
What are the components of honey ?
Honey contains sugar, water and other ingredients, where Sugar gives gives sweetness, water maintain fluidity, and other components are present in a least amount and the differences are the color, aroma and taste.
Three types of sugar such as fructose (41%), grape sugar or glucose about 34% and sucrose contain 1 and 2%, other components include minerals, proteins, acids and undetermined matter.
Minerals constitute 3.68%, increase the value of honey for human consumption and the most common minerals are potassium, chlorine, sulfur, calcium, sodium, phosphorus, magnesium, silicon, iron, manganese and copper.
Proteins are collected from nectar and pollen which is the integral parts of plants, acids are also the component, vitamn C and some B complex vitamins such as riboflavin, pantothenic acid, pyridoxine, biotin, nicotinic acid are present.
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Which of the following is an example of ionization of an acid?
O NH3(g) + H2O(1)
→ NH4+(aq) + OH (aq)
None are correct
NaCl(aq) + AgNO3(aq)
→ AgCl(s) + NaN Na(aq)
HF(aq) + H2O(1)
→ H3O+(aq) + F (aq)
Au(NO3)3(aq) + Cu(s)
→ Au(s) + Cu(NO3)2(aq)
Answer:
NH3(g) + H2O(1) → NH4+(aq) + OH (aq)
HF(aq) + H2O(1) → H3O+(aq) + F (aq)
Explanation:
Acid-base reactions are chemical reactions involving acids and bases. Acids tend to ionize/dissociate in water, a property which determines their strength. Ionization of an acid refers to the acid losing its hydrogen ion (H+) in water solution. An acid ionizes or dissociates to form a conjugate base.
A strong acid is so because it ionizes completely in water i.e. loses all its hydrogen ion (H+) while a weak acid partially ionizes in water.
In the chemical reactions;
1) NH3(g) + H2O(1) → NH4+(aq) + OH (aq)
H20 loses its hydrogen ion (H+) in this reaction to form an anion (OH-). Hence, water (H20) is an acid in this case which ionizes to form a conjugate base (OH-). This is an example of ionization of acid.
2) HF(aq) + H2O(1) → H3O+(aq) + F (aq)
Hydrogen fluoride (HF) loses its hydrogen ion (H+) in the presence of water to form anion (F-). The HF is the acid while F- is it's conjugate base. Thus, an example of ionization of acid
c. What is the mathematical equation for the total pressure below the
surface of a fluid that has air above it? Identify each variable. (1 point)
Answer: Specific gravity=Density of material/Density of water
Explanation:
https://courses.lumenlearning.com/suny-osuniversityphysics/chapter/14-1-fluids-density-and-pressure/
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
SUPPLEMENTARY QUESTION
1. Calculate the amount of heat (in calories) absorbed when 50 g of water at 20°C spreads over your skin and
warms to body temperature, 370C?
Answer:
850 Calories.
Explanation:
The following data were obtained from the question:
Mass (M) = 50 g
Initial temperature (T1) = 20 °C
Final temperature (T2) = 37 °C
Specific heat capacity (C) of water = 1 cal/g°C
Heat absorbed (Q) =..?
Next, we shall determine the change in temperature of water.
This can be obtained as follow:
Initial temperature (T1) = 20 °C
Final temperature (T2) = 37 °C
Change in temperature (ΔT) =..?
Change in temperature (ΔT) = T2 – T1
Change in temperature (ΔT) = 37 – 20
Change in temperature (ΔT) = 17 °C
Finally, we shall determine the heat absorbed. This can be obtained as follow:
Mass (M) = 50 g
Specific heat capacity (C) of water = 1 cal/g°C.
Change in temperature (ΔT) = 17 °C
Heat absorbed (Q) =..?
Q = MCΔT
Q = 50 x 1 x 17
Q = 850 Calories
Therefore, the heat absorbed is 850 Calories.
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 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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The atomic number of manganese (Mn) is 25. What's the electron configuration for manganese?
A. [Ar] 3s5 4p2
B. [Ne] 3d7
C. [Ne] 452 3p5
D. [Ar] 3d5 4s2
Answer:
[tex]\boxed{\sf D. \ [Ar] \ 3d5 \ 4s2}[/tex]
Explanation:
Manganese is a group 7 transition metal with an electronic configuration of [Ar] 3d5 4s2.
The atomic number of manganese (Mn) is 25. The electron configuration for manganese is [Ar] [tex]\rm 3d^5 4s^2[/tex]. Therefore, the correct option is option D.
The electron configuration depicts how electrons are dispersed throughout an atom's energy levels and orbitals. Manganese (Mn) has an atomic number of 25, meaning that the atom contains 25 electrons. Manganese (Mn) has the following electron configuration: [tex]\rm 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^5[/tex]
We can use the noble gas notation to indicate the electron configuration in a more compact form by indicating the noble gas that comes before the electron configuration. The noble gas that comes before manganese (Mn) is argon (Ar), whose electron configuration is[tex]\rm 1s^2 2s^2 2p^6 3s^2 3p^6[/tex]. The electron configuration of manganese (Mn) can be expressed as [tex][Ar] 3d^5 4s^2[/tex] using noble gas notation.
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Which of the following statements is true?
A Question Progress A
A. Factors that affect the reaction rate can increase the speed of a reaction but not the
yield.
O
B. None of these
C. Catalysts are important to industry to increase product yields
D. A reaction can be sped up by reducing the surface area of solid reactants.
Reset Selection
Answer:
c
Explanation: c
The statement that is true from the following is catalysts are important to the industry to increase product yields. The correct option is C.
What is a catalyst?Catalysts are substances that speed up or increase the rate of reaction. The biological catalysts are enzymes. Enzymes are made up of proteins, and they are used in the reaction to increase the yield in less time. Catalyst does not mix with the process and after the reaction.
There are many chemical catalysts like nickel and iron. These catalysts are used in chemical and manufacturing processes. They impact, accelerate, and promote the reaction to get different yields.
Thus, the correct option is C. Catalysts are significant to industry to increase product yields.
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Calculations
Weight of acetanilide = 2.7g
Theoretical yield of Nitroaniline =
Weight of para-nitroaniline = 1.5g
Percentage yield of para-nitroaniline =
Please help me which this and show me how you get the answer thank you
Answer:
Theoretical yield: 2.75g of paranitroaniline
Percentage yield: 54.5%
Explanation:
In strong-acid medium, acetanilide (Molar mass: 135.16g/mol) reacts producing para-nitroaniline (138.12g/mol) in a 1/1 reaction.
Theoretical yield of para-nitroaniline is the mass produced assuming a yield of 100%. That is:
2.7g acetanilide × (1mol / 135.16g) = 0.020 moles of acetanilide.
Assuming a yield of 100% are 0.020 moles of paranitroaniline. Theoretical yield is:
0.020 moles × (138.12g / mol) =
Theoretical yield: 2.75g of paranitroanilinePercentage yield is:
(Actual yield / theoretical yield) × 100
Actual yield was 1.5g and percentage yield will be:
Percentage yield: (1.5g / 2.75g) × 100
Percentage yield: 54.5%Give the IUPAC name of the given compound.
(CH3)-CH(NH2)-CH3
this compound is called 2-propanamine 2 indicates the position of the amino group propan- indicates the radical (joy123333 do they make anyone a mod?)
What is DNA? A. A Carbohydrate B. A protein C. A nucleic acid D. A lipid
Answer:
C: a nucleic acid
Explanation:
The function of nucleic acids is to store and express genetic information. Since fragments of DNA called genes encode the information to produce certain proteins, they are classified as nucleic acids.
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Given: 8CO + 17H2 → C8H18 + 8H2O In this chemical reaction, how many grams of H2 will react completely with 6.50 moles of CO? _______ grams of H2 will react completely
Answer:
27.63 g of H2.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
8CO + 17H2 → C8H18 + 8H2O
Thus, we can say that:
From the balanced equation above,
8 moles of CO reacted with 17 moles of H2.
Next, we shall determine the number of mole H2 that will react completely with 6.50 moles of CO.
This can be obtained as illustrated below:
From the balanced equation above,
8 moles of CO reacted with 17 moles of H2.
Therefore, 6.5 moles of CO will react with = (6.5 x 17)/8 = 13.813 moles of H2.
Therefore, 13.813 moles of H2 is needed to react completely with 6.50 moles of CO.
Finally, we shall convert 13.813 moles of H2 to grams. This can be achieved by doing the following:
Molar mass of H2 = 2x1 = 2 g/mol
Mole of H2 = 13.813 moles
Mass of H2 =.?
Mole = mass /molar mass
13.813 = mass of H2 /2
Cross multiply
Mass of H2 = 13.813 x 2
Mass of H2 = 27.63 g
Therefore, 27.63 g of H2 is needed for the reaction.
When the equation below is balanced with the lowest possible whole number coefficients, what is the sum of the coefficients? Ca(s) + HCl(g) → CaCl2(s) + H2(g)
Answer:
ca(s)+hcj(g)cacI 2 (s)+H2(g)
Explanation:
The equation below is balanced with the lowest possible whole-number coefficients, the sum of the coefficients Ca(s) + HCl(g) → CaCl2(s) + H2(g) is
ca(s)+hcj(g)cacI 2 (s)+H2(g).
What is the sum of the coefficients when the equation for the combustion of ammonia is balanced using the smallest possible whole numbers?The sum of the coefficients is 2+3+4+3=12.
What type of reaction is Ca 2hcl → CaCl2 H2?Type of Chemical Reaction: For this reaction, we have a single displacement reaction. Balancing Strategies: In this reaction Calcium (Ca) metal is reacting with Hydrochloric acid (HCl). the Ca replaces the H in HCl and we end up with CaCl2 and H2.
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