Answer:
When you heat ice, its temperature rises, but as soon as the ice starts to melt, the temperature stays constant until all the ice has melted. This happens because all the heat energy goes into breaking the bonds of the ice's crystal lattice structure.
Explanation:
The temperature stop rising while ice melts into water because, the energy is being absorbed to separate the particles. This is because of latent heat of fusion.
What is latent heat of fusion?The amount of energy needed to convert the solid substance into a liquid substance by modifying its physical effects. It exists also named enthalpy of fusion. When heat exists supplied to ice, it begins melting and heat is used to increase temperature initially. But after the occasional temperature of ice does not vary and the extra heat exists utilized to melt the ice by cracking bonds between crystal lattice of ice.
The temperature stops increasing while the ice melts into the water because the energy exists being absorbed to divide the particles. This exists because of the latent heat of fusion.
Therefore, (D) option is the correct answer.
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19. Which type of chemical process is used to remove salt from ocean water?
O A. Alkylation
O B. Doping
O C. Dehydrogenation
D. Desalination
Answer:
D
Explanation:
Desalination
Removing salt from sea water is known as desalination
Explain the difference between temperature and thermal energy.
Explanation:
the difference between temperature and thermal energy are as follow ,
• The thermal energy, or heat, of an object is obtained by adding up the kinetic energy of all the molecules within it. Temperature is the average kinetic energy of the molecules.
Provide the name of the compound shown below. Spelling and format counts!
CH3
NO2
NO2
Answer:
ch3:-methanide
No2:-nitrogen dioxide
thank you and mark as brainliest if u find it helpful
which of the following is is a chemical property of pure water
Answer:
Pure water has an acidity of about 7 on the pH scale. -is a chemical property of pure water. Pure water has an acidity of about 7 on the pH scale
Answer: không màu , không mùi không vị
Explanation:
What is the basic unit of chemistry?
O A. The bond
O B. The atom
O C. The sun
O D. The cell
Answer:
B. The atom
Explanation:
Cells are the most basic unit of structure and the smallest unit of matter is the atom.
Answer:
B. The atom
Explanation:
yeee it was right
You are working in a lab when radiation alarms go off. You are able to hide inside a steel cabinet, whose sides are about 1.5 inches thick, until the alarm goes off. Preliminary reports show that the radiation was weakly ionizing and negatively charged. Were you safe in the cabinet?
A. Yes, it was beta radiation and the steel was enough to block it.
B. Yes, it was alpha radiation and not harmful.
C. No, it was beta radiation and very dangerous.
D. No, it was gamma radiation and can only be blocked by a thick wall of lead.
Answer
A
Explanation:
Beta radiation is only very dangerous when it is ingested or if there is nothing in the way. The steel should protect you.
Yes, it was beta radiation and the steel was enough to block it. Hence, option A is correct.
What is beta radiation?Beta radiation is a current of electrons released at a rate exceeding the speed of light, with kinetic energy between 0.2 MeV and 3.2 MeV. Due to their lower mass which is approximately 5.5×[tex]10^{-4}[/tex] amu (9.130×[tex]10^(-24)[/tex], interactions between β-particles and the atoms of pass-through materials are much less frequent than the interactions between 5-007-particles: less than 200 ion pairs are typically formed in each centimetre of the air passage.
When we are working in a lab when radiation alarms go off and we are able to hide inside a steel cabinet, whose sides are about 1.5 inches thick, until the alarm goes off.
Preliminary reports show that the radiation was weakly ionizing and negatively charged. Yes, it was beta radiation and the steel was enough to block it.
Hence, option A is correct.
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If you drip an ink drop into a cup of water and wait for a few seconds, all the water will be colored with the ink. This experiment is an example of facilitated diffusion ?
true
false
Answer:
false, it is not an example of facilitated diffusion
Answer:
TrueExplanation:
When a drop of ink added into the water gradually moves in the whole quantity of water due to this entire water turns into blue color. This is nothing but the diffusion of ink particles into the water molecules. This is because water, as well as ink molecules, are in random motion due to the motion of ink substance.
how hydrogen chloride gas is prepared on labrotary by conc sulpheric acid
Answer:
It is prepared small amounts of hydrogen cloride for uses in the lab.
It can be "generated in an HCl generator by dehydrating hydrochloric acid with either sulfuric acid or anhydrous calcium chloride."
Why is ice cold water rather than room temperature or warm water used to wash the remainder of the benzoic acid out of the beaker?
As a general rule:
"Solubility of compounds decrease with the increasing of temperature" as you can see in the graph.
Also, filtration, is a chemical process where you are separating a precipitate from a solution.
Now, if you want to recover benzoic acid from an aqueous solution, the better option would be with Ice cold water because its solubility will be lower because temperature is lower producing more precipitate.
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11. How many oxygen atoms are there in one formula unit of Ca2+?
Answer:
NO3 has 3 atoms of oxygen in it per molecule (indicated by the subscript of 3) and (NO3)2 means you have 2 NO3 molecules, meaning you double the subscript to get 6 oxygen atoms
HELP! How is the mass number of an atom calculated?
A - total number of electrons
B - total number of protons
C - protons plus neutrons
D - electrons plus neutrons
A tank contains oxygen gas at 2.551 atm. What is the pressure in mmHg?
The force exerted on the container by the particles of the matter is called pressure. The tank containing oxygen gas at 2.551 atm will have a pressure of 1939 mm Hg.
What is pressure?Pressure is the property used to estimate the force experienced by the system due to the liquid or the gas held in it. The pressure of the gas can be calculated by the ideal gas and force and area.
The pressure is created due to the collision of the particles of the gases and liquids on the wall perpendicularly. It is estimated in Pascal (Pa) as the standard unit along with atm and mmHg.
It is known that 1 atm = 760 mm Hg
Given,
The pressure of oxygen gas = 2.551 atm
Using the conversion factor the pressure from atm to mm Hg is calculated as,
1 atm = 760 mm Hg
2.551 atm = (2.551 atm × 760 mm Hg) ÷ 1 atm
= 1938.76 mmHg
Therefore, 1939 mm Hg is the pressure of the oxygen gas.
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Lead of mass 0.75kg is heated from 21°c to its melting point and continues to be heated unit it has all melted. Calculate how much energy is supplied to the lead. [Melting point of lead 372.5°c specific latent heat of fusion of lead = 23000 Jkg 'k ']
Answer:
65.5J
Explanation:
ML=Q
ML=MC(change in temperature)
0.75 X 23000 =0.75 X 351 X C
C= 65.5J
The energy supplied to the lead to melt from 21°c to its melting point is 51521 Joules.
What is the specific heat capacity?Specific heat is the amount of heat energy supplied to change the temperature of one unit mass of a substance by 1 °C. The SI unit of the specific heat capacity of a substance is J/Kg.
The mathematical expression for the specific heat capacity can be written as:
Q = mCΔT Where C is the specific heat of the substance.
The specific heat capacity depends upon the starting temperature and is an intensive characteristic of the material.
Given, the melting point of the lead T₂ = 327.5° C
The initial temperature of the lead, T₁ = 21° C
The latent heat of the lead given, L = 230000 J/Kg K
The specific heat of the lead, C = 130 J/Kg K
The heat required to melt the lead from 12°C to 327.5 °C is :
Q = m× [C × (T₂ - T₁) + L ]
Q = 0.75 × [0.130 (327.5 - 21) + 23000]
Q = 51521 J
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How many moles of tetracycline (C₂₂H₂₄N₂O₈) are in 71.9 grams
Explanation:
to find the number of moles for tetracycline you use the formula,
number of moles=mass/molar mass
the mass is given in the question which is 71.9g and the molar mass is 444.43(you find I by adding the number of atoms for each element in the compound,12×22+1×24+14×2+16×8)
n=71.9g/444.43
=0.16g/mol
I hope this helps
A water chemist measured and recorded the air temperature at 27°C when he should have measured the water temperature, which was only 21°C. As a result of this error, will the dissolved oxygen concentration be reported as being higher or lower than it should be? Explain.
Answer:
See explanation
Explanation:
The dissolution of oxygen in water is exothermic. Hence, at higher temperature, less oxygen is dissolved in water.
If the chemist commits an error and records 27°C instead of 21°C, the dissolved oxygen concentration will be found to be lower than it should be at 27°C because dissolution of gases in water is exothermic.
Which one of the following compounds will be soluble in water?
A) AgCI
B) PbCO3
C) CaSO4
D) Cu(OH)2
E) LiCl
The compound that has been soluble in water will be LiCl. Thus option E is correct.
The compounds that form stable bonds in water and are easy to dissociate are soluble in water. Generally, ionic compounds are easily soluble in water.
AgCl:It has been an ionic compound, but the dissociation of AgCl will simultaneously form AgCl again making the compound insoluble in water.
[tex]\rm \bold{PbCO_3}[/tex]:It has been a covalent compound, thus it has been insoluble in water.
[tex]\rm \bold{CaSO_4}[/tex]:The compound is covalent in nature, thus it has been hard to dissociate in water.
[tex]\rm \bold{Cu(OH)_2}[/tex]:The copper in the compound has been hard to dissolve and precipitate in the solution.
LiCl:It has been an ionic compound and can be easily dissociated in the water.
Thus the compound that has been soluble in water will be LiCl. Thus option E is correct.
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Name the following alkane molecule:
CH3
CH3CCH3
CH3
A. 2-ethylpropane
B. 2-dimethylpropane
C. 2,2-dimethylpropane
not 100% sure but I think its C
The correct name for the given alkane molecule is 2,2-dimethylpropane. (Option C)
The given alkane molecule is composed of three carbon atoms. The central carbon atom is bonded to two methyl groups (CH₃) on either side. This results in a branched structure where the methyl groups are attached to the same carbon atom.
According to the rules of IUPAC nomenclature, the prefix "2,2-" indicates that the methyl groups are attached to the second carbon atom in the main chain. The parent chain, which consists of three carbon atoms, is named propane. Since there are two identical methyl groups attached to the second carbon atom, the compound is named 2,2-dimethylpropane.
Hence, the name of the given alkane molecule is 2,2-dimethylpropane.
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Determine the volume of H2 gas needed to react completely with 5.00L of Oz to form water
10.0L
20L
b 5L
d. 15L
Answer: 10.0 L
Explanation:
I need to know what is the median of the data
Answer:
The median is also the number that is halfway into the set. To find the median, the data should be arranged in order from least to greatest. If there is an even number of items in the data set, then the median is found by taking the mean (average) of the two middlemost numbers.
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in non- equilibrium cooling, carbon is allowed to diffuse its end position. true /false
Answer:
False because it is false
MnO₄- chemical name for ALEKS
Mno4- chemical name is permanganate
A central atom has two lone pairs on opposite sides and four single bonds. What is the molecule geometry of the result?
A. octahedral
B. tetrahedral
C. square planar
D. linear
The correct answer is C. square planar
According to the Valence Shell Electron Pair Repulsion Theory(VSEPR), The shape of a molecule depends on the number of electron pairs in the molecule.
VSEPR theory was first coined by Gillespie and Nyhlom in 1957 as an improvement over the Sidgwick - Powell theory.
According to this theory, the shape of a molecule is determined by the number of electron pairs that surround the valence shell of the central atom in the molecule. The electron pairs are positioned as far apart in space as possible to minimize repulsion of electron pairs.
However, the presence of lone pairs distorts the shape anticipated for the molecule on the basis of VSEPR.
For a molecule having six electron pairs, an octahedral geometry is expected(electron domain geometry). However, the presence of two lone pairs which are positioned at opposite side of the four single bonds leads to an observed square planar molecular geometry.
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Answer:
square planar
Explanation:
s-Block compounds give a characteristic flame colour in the flame test. Based on this, can you give one use of s-block compounds?
Answer:
Lithium is used in making electrochemical cells.
Why is the r.a.m. Value used?
Answer:
The r.a.m. value is used to determine how many isotopes an element has.
Explanation:
Why must oxidation be accompanied by a reduction?
A. The species being oxidized shares electron(s) with the species that is reduced
B. The species being oxidized takes electron(s) from some other
C. Electrons can be given up to free space. species being oxidized must transfer electron(s) to some othen
D. Electrons cannot just be given up to free space.
Answer:
A
Explanation:
because the species being oxidized shares electrons with the species that is reduced.making the oxidized element positively charged and the reduced element negatively charged.
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Alphabet:B. the species being oxidized takes electron from some other
explain chlorination of methane
Answer:
Methane and chlorine
If a mixture of methane and chlorine is exposed to a flame, it explodes - producing carbon and hydrogen chloride. This is not a very useful reaction! The reaction we are going to explore is a more gentle one between methane and chlorine in the presence of ultraviolet light - typically sunlight. This is a good example of a photochemical reaction - a reaction brought about by light.
CH4+Cl2+energy→CH3Cl+HCl(3.4.2)
The organic product is chloromethane. One of the hydrogen atoms in the methane has been replaced by a chlorine atom, so this is a substitution reaction. However, the reaction doesn't stop there, and all the hydrogens in the methane can in turn be replaced by chlorine atoms.
Substitution reactions happen in which hydrogen atoms in the methane are replaced one at a time by chlorine atoms. You end up with a mixture of chloromethane, dichloromethane, trichloromethane and tetrachloromethane.
I hope this help you!:)
Explanation:
calcium is added to water,the liberated gas is
Answer:
In both cases, the gas evolved is H2. When calcium reacts with water the heat evolved is not suffcient for hydrogen to catch fire. On the other hand, sodium metal reacts with water violently and in this case a lot of heat is evolved which is sufficient for hydrogen to catch fire.
Explanation:
may this answer is helpful for you
Hydrogen
The reaction is given by
[tex]\boxed{\sf {Ca\atop Calcium}+{H_2O\atop Water}\longrightarrow {Ca(OH)_2\atop Calcium\:Hydroxide}+{H_2\atop Hydrogen}}[/tex]
Balanced equation:-
[tex]\boxed{\sf {Ca\atop Calcium}+{2H_2O\atop Water}\longrightarrow {Ca(OH)_2\atop Calcium\:Hydroxide}+{H_2\atop Hydrogen}}[/tex]
convert 100kcals to kilojoules
Answer:
Explanation:
418.4kj is the correct answer
Alex drips hydrochloric acid onto a 5.9 g piece of magnesium in a single displacement reaction. How many molecules of HCl are required? 2HCl(aq) + Mg(s) → MgCl2(aq) + H2(g)
how do you do this?
2.96 × 10²³ molecules is required if Alex drips hydrochloric acid onto a 5.9 g piece of magnesium in a single displacement reaction
According to this question, hydrochloric acid (HCl) reacts with magnesium metal (Mg) to produce magnesium chloride and hydrogen has as follows:
2HCl(aq) + Mg(s) → MgCl2(aq) + H2(g)
Based on the balanced chemical equation above; 2 moles of HCl reacts with 1 mole of Mg. Next, we convert 5.9g of Mg to moles by using the formula; mole = mass/molar massWhere; Mg = 24g/mol
mole = 5.9/24
mole = 0.246mol of Mg
If 2 moles of HCl reacts with 1 mole of Mg. 0.246 mol of Mg will react with (0.246 × 2) = 0.492mol of HClTo convert mole to number of molecules, we multiply number of moles by 6.02 × 10²³ (Avogadro's no.)
Hence, number of molecules of HCl required is 0.492mol × 6.02 × 10²³
= 2.96 × 10²³ molecules of HClHCl
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Test Question just answer random.
Answer:
U are a fool
Explanation:
Because you didn't even asked a question
Answer:
k.
Explanation:
