Answer:
C I believe not quite sure tho
In heating and melting curves, the name of the heat associated with the solid-liquid phase is Heat of fusion.
What is the Heat of fusion ?
The standard fusion enthalpy is the amount of thermal energy required for a single mole of a substance to change states from a solid to a liquid or vice versa is known as the heat of fusion or specific melting heat. The melting point is the temperature at which it takes place, and it is also known as the latent heat of fusion or the enthalpy change of fusion.The temperature of a liquid or solid goes down when thermal energy is taken away. The temperature rises when heat and energy are added. However, additional energy—the heat of fusion—is required at the melting point—the transition point between solid and liquid. The molecules of a substance need to become more organized in order to change from liquid to solid. They require the withdrawal of additional heat in order to maintain their solid state. In the opposite direction, additional heat is required to induce the disorder from the solid crystal to the liquid.The temperature of water as it freezes can be measured to observe the heat of fusion. When you place a closed container of room temperature water in a very cold environment, say 20 °C, the temperature will gradually fall until it is just below the freezing point. After that, the temperature rises and stays the same as the water crystallizes. The temperature will again fall steadily after it has completely frozen.The heat of fusion causes the temperature to stop falling at (or just below) the freezing point. Before the temperature can continue to fall, the energy from the heat of fusion must be removed—the liquid must transform into a solid.
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Hello, I am stuck on a chemistry question. Would you be able to help? You arrive at a crime scene and are told the body of the victim is at the bottom of a pool that is 10 m deep. You walk over to what you are told is a 12 m in diameter, cylindrical pool. From the outside of the pool, you can see that the body looks badly burnt. Your partner says, “It looks like our victim had been burned alive and tried to put out the fire by jumping in the pool. The victim likely drowned to death.”
Something does not sit right with you though. If there was a fire, where did it start? There are no signs of combustion anywhere. You aren’t so sure and ask the crime scene investigator to run a sample of the pool water before letting anybody try to pull the body out.
The CSI comes back to you and tells you that normal pool water pH is roughly around 7.2, but the pool pH is actually highly basic at a level of 13, with a concentration of hydroxide ions at 1.0 x 10-1 mol/L. It becomes obvious to you that the body wasn’t burned before going in to the pool, but AFTER, and there was no fire needed!
You order the body to be removed from the pool, but the CSI interjects, “It would be too dangerous with a pH that high. I suggest you get some vinegar from the store and pour it in to the pool beforehand to drop the pH to 7. Draining the pool would take far too long and we need to examine the body as soon as possible.” She asks one of your constables to go to the store to purchase five 4L jugs of vinegar (pH = 2) to pour in the pool, as she states it is enough to bring the pH to a safe level of 7.
It sounds like it could be enough vinegar based on your knowledge of acids and bases, but you want to double-check her estimate before sending your constable to the store. Verify whether or not she is correct using calculations. A diagram may help you with your calculations.
Hint 1: 1m3 = 1000L
Hint 2: Vcylinder = πr2h
Answer:
The vinegar is not enough to neutralize the pool.
Explanation:
The [OH⁻] in the pool is 1.0x10⁻¹mol / L. To know how many moles of OH⁻ are in the solution, you must calculate volume of the pool thus:
V(pool) = πr²h
Where r, radius is d/2 = 12m/2 = 6m and h is deep of the pool = 10m
V(pool) = π(6m)²*10
V(pool) = 1131m³
As 1m³ = 1000L:
1131m³ × (1000L / 1m³) = 1131000L in the pool.
And moles of OH⁻ are:
1.0x10⁻¹mol / L ₓ 1131000L = 131100 moles of OH⁻ are in the pool
The neutralization of OH⁻ with H⁺ is:
OH⁻ + H⁺ → H₂O
That means to neutralize the pool you must add 131100 moles of H⁺.
The H⁺ concentration in a vinegar pH = 2 is:
pH = -log [H⁺]
2 = -log [H⁺]
1x10⁻²M = [H⁺]
4L are just 4x10⁻² moles of [H⁺]. As you need 131100 moles of H⁺:
The vinegar is not enough to neutralize the pool.What would be the charge on an ion whose neutral atom has an electron configuration of 2.8.7?
O A. +7
OBO
C. +1
Answer:
–1
Explanation:
The electronic configuration of the neutral atom is given below:
2 8 7
From the electronic configuration of the neutral atom, we can see that the atom has 7 electrons in it's outermost shell. This implies that the element needs 1 more electron to complete it's octet configuration.
Therefore the charge on the ion of the element will be –1 indicating that the atom has received 1 electron to complete it's octet configuration.
Matter is composed of exceedingly small particles called atoms. An atom is the
smallest unit of an element that can participate in a -------
Answer:
Matter is composed of exceedingly small particles called atoms. An atom is the
smallest unit of an element that can participate in a chemical reaction.
Answer:
Chemical reaction.
Explanation:
Give two reasons why mixing and heating sulphur powder and iron filings on a watch glass is chemical change
Answer:
When iron filings and sulphur powder are mixed and heated they undergo a chemical reaction and form ferrous sulphide (FeS). It is a new substance which has properties entirely different from Fe and S. Therefore, heating of mixture of iron and sulphur powder is a chemical change.
1. The atomic symbol of aluminum is written as 2713Al. What information do you get from it?
Answer:
its mass number and atomic number
Explanation:
atlmic number(subscript)=13
mass number(superscript)=27
what is heat energy
Answer:
Movement of tiny particles called atoms, molecules and ions in a solids,liquid and gases. Heat energy can be transferred from one object to another. The transfer or flow due to the difference in temperature between the two objects is called heat.
What is organic chemistry
Explanation:
Hi there!!!
The organic chemistry is a branch of chemistry which deals with the study of hydrocarbons compounds. organic chemistry deals with the study of structure, properties and reactivity of carbon compounds. It is a very broad area where more than 100000 organic compounds are studied.
Hope it helps..
how many sigma and pi bonds in propionic bond
Which of the following elements does not lose an electron easily? NA F MG AL
Answer:
F
EXPLANATION
Among the given elements fluorine(F)can not lose electrons easily because of its high electron affinity, high nuclear charge and high electronegativity.
Answer:
F
Explanation:
it won't lose electron , rather it would gain electron to complete its octate......
Electronic Configuration of F = 2,7
So F will gain 1 electron ....
what is an electrolyte? the fastest answer will get bainliest.
Answer:
Electrolytes are substances which undergo chemical change when electricity is passed through them.
A 35 L tank of oxygen is at 42°C with an internal pressure of 5000.mmHg. If the temperature changes to 88°C, what would the new pressure be ? the volume is held constant
Answer:
5730 mmHg.
Explanation:
The following data were obtained from the question:
Initial temperature (T1) = 42 °C.
Initial pressure (P1) = 5000 mmHg.
Final temperature (T2) = 88 °C.
Final pressure (P2) =.?
Next we shall convert celsius temperature,T(°C) to Kelvin temperature, T(K).
This can be obtained as follow:
T(K) = T(°C) + 273
Initial temperature (T1) = 42 °C.
Initial temperature (T1) = 42 °C + 273 = 315 K
Final temperature (T2) = 88 °C.
Final temperature (T2) = 88 °C + 273 = 361 K
Finally, we shall determine the new pressure.
Since the volume of the container is constant, the new pressure can be obtained as follow:
Initial temperature (T1) = 315 K.
Initial pressure (P1) = 5000 mmHg.
Final temperature (T2) = 361 K.
Final pressure (P2) =.?
P1/T1 = P2/T2
5000/315 = P2/361
Cross multiply
315 x P2 = 5000 x 361
Divide both side by 315
P2 = (5000 x 361) / 315
P2 = 5730.1 ≈ 5730 mmHg
Therefore, the new pressure is 5730 mmHg.
Na-23 has 12 neutrons. What is it’s atomic number?
Answer:
11
Explanation:
Data obtained from the question include:
Mass number = 23
Neutron = 12
Atomic number =.?
Next, we shall determine the number of protons present in the element.
This can be achieved by doing the following:
Mass number = Proton + Neutron
Mass number = 23
Neutron = 12
Proton =...?
Mass number = Proton + Neutron
23 = Proton + 12
Collect like terms
Proton = 23 – 12
Proton = 11
The atomic number of an element is equal to the proton number.
Atomic number = proton number
Proton number = 11
Atomic number = proton = 11
Therefore, the atomic number is 11.
What type of reaction is: ammonium nitrate -> dinitrogen monoxide + water?
Answer:
The thermal decomposition of ammonium nitrate to produce dinitrogen monoxide and water. This reaction takes place at a temperature of 200-260°C.
How can the rate constant be determined from the rate law
Answer: The rate constant is the reaction rate divided by the concentration terms.
The reaction between hydrogen gas and chlorine gas produces hydrogen chloride according to the following equation: H2(g) + Cl2(g) → 2HCl(g). Using the following bond enthalpies(D) calculate the enthalpy of reaction. D(H-H) =436 kJ/mol; D(Cl-Cl) = 243 kJ/mol D(H-Cl) = 432 kJ/mol
Answer:
The enthalpy of reaction is -185 kJ
Explanation:
To get the reaction:
H₂(g) + Cl₂(g) → 2 HCl(g)
you must follow the following steps:
1) Reactive molecules must break their bonds to obtain their atoms.
H₂(g) → 2 H(g)
Cl₂(g) → 2 Cl(g)
Bond energy (or enthalpy) is the energy required to break one mole of bonds of a gaseous substance. In the case of diatomic molecules with a single bond, it corresponds to the energy necessary to dissociate 1 mole of said substance in the atoms that form it.
Whenever you want to break links you must supply energy, so the link enthalpy will have positive values; while when a mole of bonds is formed energy is released and the bond enthalpy of this process will be negative.
In this case you will then have:
H₂(g) → 2 H(g) ΔH=436 kJ/mol
Cl₂(g) → 2 Cl(g) ΔH=243 kJ/mol
So the total energy needed to break all the bonds is:
ΔH=1 mol*436 kJ/mol +1 mol* 243 kJ/mol= 679 kJ
2) The atoms that were obtained in the break of the bonds must be combined to obtain the product.
2 H (g) + 2 Cl (g) → 2 HCl (g)
Being the single bond energy for one mole of 431 kJ H-Cl bonds and considering that two moles of H-Cl bonds are formed, the ΔH is:
ΔH = -2 moles* (432 kJ/mol) = -864 kJ
As mentioned, when a mole of bonds is formed energy is released, the bond enthalpy of this process will be negative. So the formation of HCl is negative.
Hess's law states that the energy change in an overall chemical reaction is equal to the sum of the energy changes in the individual reactions comprising it. So:
ΔHtotal= -864 kJ + 679 kJ
ΔHtotal= -185 kJ
The enthalpy of reaction is -185 kJ
When lithium metal reacts with fluorine gas it forms the ionic compound lithium fluoride (LiF). What is the correct electron configurations of the ions formed
Answer:
The electronic configuration of ions formed are:
Li+ (2) => 1s2
Cl- (18) => 1s2 2s2 2p6 3s2 3p6
Explanation:
Lithium metal, Li will lose 1 electron to lithium ion Li+. Chlorine atom, Cl will receive the 1 electron to form the chloride ion Cl- as shown by the following equation below:
Li —> Li+ + e
Cl+ e —> Cl-
Combine both equation
Li + Cl + e —> Li+ + Cl- + e
Cancel out 'e'
Li + Cl —> Li+ Cl-
Thus, we can write the electronic configuration for the reaction as follow:
Before reaction:
Li (3) => 1s2 2s1
Cl (17) => 1s2 2s2 2p6 3s2 3p5
After reaction
Li+ (2) => 1s2
Cl- (18) => 1s2 2s2 2p6 3s2 3p6
Therefore, the electronic configuration of the ions formed are:
Li+ (2) => 1s2
Cl- (18) => 1s2 2s2 2p6 3s2 3p6
In which particle model are the red and blue particles MOST LIKELY to bump into each other? PLEASE HELP WILL MARK BRAINLIEST!!
Answer:
441
Explanation:
In particle model A are the red and blue particles MOST LIKELY to bump into each other and the correct option is option A.
What is Particle Model of Matter?The particle model of matter is a theory that explains how the particles that make up a substance are arranged, and how they move and interact with each other.
The particle model explains the properties of solids, liquids and gases. The particle model can explain changes of state.
Particles of matter have spaces between them. Atoms and molecules have spaces between them. In a gas, there are large spaces between them. In a a liquid they are closer together. In a solid, the particles are packed close enough together they can hardly move.
Therefore, In particle model A are the red and blue particles MOST LIKELY to bump into each other and the correct option is option A.
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Explain why all glassware must be dry and the solvent anhydrous during formation and reaction of a Grignard reaction. Explain why it is advisable to not clean your glassware with acetone before a Grignard reaction. Include balanced chemical equations in your answer. (4 pts)
Answer:
The Grignard reagent will be destroyed
Explanation:
The Grignard reaction is based on a carbanion production (RMgX). If water is present in the glassware, a reaction can take place with [tex]H_2O[/tex] and the desired product will not be produced. Because an "H" would be transferred from water to the Grignard reagent. (See figure 1)
If we have acetone in the glassware we will have a similar problem. The Grignard reagent would be destroyed and the desired product will not be produced. The Grignard reagent will attack the carbon in the carbonyl group and the carbanion would disappear. (See figure 2)
What would 12.47 rounded to 2 sig figs be?
Answer:
12
Explanation:
To get to this answer you have to look at the number first. So the given number is 12.47 and you need 2 sig figs.
To help you understand this more start off by underlining the first 2 numbers because 2 sig figs are needed. 12.47
Now you want to look at the number after the underlined (I bolded that number). 12.47
If the number is above 5 then you would round the previous number up by one but in this case it is 4 so you do not increase the number. Hence, you getting 12 as your final answer.
Hope this helped! Let me know if you have any questions.
To what temperature should 2.3L of a gas at 25degree Celsius be heated in order to expand its volume to 4 L under constant pressure
Answer:
518.52K
Explanation:
Charles law, which describes the direct relationship between the volume and the temperature of a gas when the pressure is constant, will be used for this question. The Charles law equation is:
V1/T1 = V2/T2
Where; V1 is the volume of the gas at an initial state (Litres)
T1 is the absolute temperature of the gas at an initial state (Kelvin)
V2 is the volume of the gas at a final state (Litres)
T2 is the absolute temperature of the gas at a final state (Kelvin)
According to the question, V1 = 2.3L, T1 = 25°C, V2 = 4L, T2 = ?
We need to convert the temperature to the absolute temperature unit in Kelvin (K) i.e.
T(K) = T(°C) + 273.15
T(K) = 25°C + 273.15
T1 (K) = 298.15K
To find for T2 in the equation, we make T2 the subject of the formula:
T2 = V2 × T1 / V1
T2 = 4 × 298.15 / 2.3
T2 = 1192.6/2.3
T2 = 518.52
Thus, the temperature must be heated to 518.52K in order to expand to a volume of 4L. This answer is in accordance to Charles law that the volume increases with increase in temperature and vice versa.
what is a conjugate acid
THE conjugate acid, within the acid–base theory, is a chemical compound formed by the reception of a proton by a base—in other words, it is a base with a hydrogen ion added to it, as in the reverse reaction it loses a hydrogen ION.
Flask is immersed in a large beaker of very hot water. At first, the level of the liquid in the tube falls, but after a short time it rises. Explain why the liquid level in the tube stops falling and starts to rise.
Answer:
Explanation:
When a flask is dipped in very hot water in a large beaker , the flask expands due to heat gain . As a result , level of water in tube fitted in flask goes down .
After some time , the water inside tube also become hot so it expands . coefficient of volume expansion of water is more than coefficient of volume expansion of glass . Hence greater expansion takes place in the volume of water . It is due to this fact that water level in tube starts rising after some time of fall .
what is the difference between the atom and isotope
Answer:
Atoms consist of a nucleus made of protons and neutrons orbited by electrons.
Isotopes are atoms that have same number of protons but they differ in the number of neutrons and in atomic mass.
Answer:
Isotopes are atoms that have the same numbers of protons but different numbers of neutrons. An ion is an atom that has gained or lost electrons, so it now has more or fewer electrons than it does protons. So an ion has a negative or positive charge.
Hope it helps :)
A student has a piece of aluminum metal what is the most reasonable assumption a student can make about the metal
Answer:
- It could be stretched into a thin wire.Explanation:
As per the question, the most rational claim that the student can make about the aluminum metal is that 'it could be stretched into a thin wire' without breaking which shows its ductility. It is one of the most significant characteristics of a metal. Metals can conduct electricity in any state and not only when melted. Thus, option A is wrong. Options C and D are incorrect as metals neither have the same shape always nor do they break on hitting with a hammer. Therefore, option E is the correct answer.
Answer:
Yes, the other person is correct; the answer is E. It could be stretched into a thin wire.
Explanation:
Here is why it is NOT B:
"A briskly burning wood fire is plenty hot enough to melt aluminum. If it's just smoldering (like a lot of campfires) it won't create enough heat to melt aluminum."
Therefore, CAMPFIRES are not likely to melt aluminum if it is thrown in. Aluminum's melting point is 1,221 ° F. Typical campfires are about 900 ° F.
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Earth’s outermost layer is separated into a dozen or more large and small slabs, called _______. A. continental crust B. tectonic plates C. granite slabs D. Pangea
Answer:
Tectonic Plates
Explanation:
Answer:
Tectonic plates
Explanation:
What mass of oxygen gas contains the same number of moles as 56g of sulphur? (Relative atomic mass: S = 32, O = 16) A) 0.56g B)5.6g C)56g D)560g
Answer:
The answer is option C
Explanation:
To calculate the mass of oxygen gas we must first find the number of moles of sulphur
Molar mass = number of moles (n) / mass
n = mass / Molar mass
From the question
Molar mass (M) of Sulphur = 32g/mol
mass = 56g
n( Sulphur) = 56/32 = 1.75mol
Since the moles of oxygen and sulphur are the same
M(O2) = 16 × 2 = 32g/mol
Mass of oxygen = molar mass × moles
= 32 × 1.75
= 56gHope this helps you
If 156.06 g of propane, C3H8, is burned in excess oxygen, how many grams of water are formed? C3H8 + O2 → CO2 + H2O Select one: a. 255.0 b. 765.1 c. 191.3 d. 31.88
Answer:
The correct option is;
a. 255.0 g
Explanation:
The given information are;
Mass of propane, C₃H₈ in the combustion reaction = 156.06 g
The equation of the combustion reaction is C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
From the balanced chemical equation of the reaction, we have;
One mole of propane, C₃H₈ reacts with five moles oxygen gas, O₂, to form three moles of carbon dioxide, CO₂, and four moles of water, H₂O
The molar mass of propane gas = 44.1 g/mol
The number of moles, n, of propane gas = Mass of propane gas/(Molar mass of propane gas) = 156.06/44.1 = 3.54 moles
Given that one mole of propane gas produces 4 moles of water molecule (steam) H₂O, 3.54 moles of propane gas will produce 4×3.54 = 14.16 moles of (steam) H₂O
The mass of one mole of H₂O = 18.01528 g/mol
The mass of 14.16 moles of H₂O = 14.16 × 18.01528 = 255.0 g
The mass of H₂O produced = 255.0 g
Give one reason why water gas and producer gas are prepared together in the same furnace. Pls ansa its urgent
Answer:
because water gas has high heat content more than producer gas
Explanation:
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how to make a salt by neutralization reaction
Answer:
Acid+Base=Salt+water
This is the formula of neutralization reaction.
According to this formula you can make salts by reacting an acid with a base.
Hope this helps ❤❤❤.
Which element would have properties most similar to those of
cesium (Cs)?
O A. Rb
B. Ca
C. Sr
D. Ba.
Answer:
Rb
Explanation:
This is because they are in the same group which means they share similar properties.
What do rubidium and cesium have in common?
This family consists of the elements lithium, sodium, potassium, rubidium, cesium, and francium (Li, Na, K, Rb, Cs, and Fr, respectively). Group one elements share common characteristics.
What are the physical and chemical properties of caesium?
It is silvery gold, soft, and ductile. It is the most electropositive and most alkaline element.
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