The best explanation for why a firework being ignited is an example of an exothermic reaction and not an endothermic reaction is:
The fireworks give off heat.
Heat is emitted into the environment in an exothermic reaction. When a firework is lit, it undergoes a number of chemical processes inside the firework combination, which produces gases and produces a great deal of heat. Fireworks' distinctive visual display and audible effects are produced when heat is released as light and sound.
In contrast, heat is taken from the environment during an endothermic reaction. If a reaction were endothermic, it would need an outside energy source to continue, and because it would be absorbing heat from its environment, it would feel chilly to the touch.
However, because they release heat and energy and brighten the night sky, fireworks are instances of exothermic reactions.
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Which statement is true for most chemical reactions?
O An energy change occurs during the breaking and forming of bonds.
O The internal energy of the system increases during a reaction.
O Energy is released during the formation of reactants.
O The enthalpy of the products is higher than the enthalpy of the reactants
Answer:
An energy change occurs during the breaking and forming of bonds.
Explanation:
Answer:
An energy change occurs during the breaking and forming of bonds.
Explanation:
Energy changes occur when bonds are broken or formed.
When a bond is formed, energy is released.
When a bond is broken, energy is stored.
Edge 2022
Thermochemical Reactions Quiz answer
How does the number of molecules in 1 mol of oxygen compare with the number of molecules in 1 mol of nitrogen?
O 1 mol of oxygen has fewer molecules.
O 1 mol of oxygen has more molecules.
O Each sample has the same number of molecules.
O The molecules cannot be compared without knowing the mass.
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Answer:
Each sample has the same number of molecules.
Explanation:
This is true by Avogadro's law.
in chemistry what is Faraday's law
Answer:
Faraday’s – First Law of Electrolysis
It is one of the primary laws of electrolysis. It states, during electrolysis, the amount of chemical reaction which occurs at any electrode under the influence of electrical energy is proportional to the quantity of electricity passed through the electrolyte.
Faraday’s – Second Law of Electrolysis
Faraday’s second law of electrolysis states that if the same amount of electricity is passed through different electrolytes, the masses of ions deposited at the electrodes are directly proportional to their chemical equivalents.
From these laws of electrolysis, we can deduce that the amount of electricity needed for oxidation-reduction depends on the stoichiometry of the electrode reaction.
The product of an electrolytic reaction depends on the nature of the material being electrolysed and the type of electrodes used. In the case of an inert electrode such as platinum or gold, the electrode does not participate in the chemical reaction and acts only as a source or sink for electrons. While, in the case of a reactive electrode, the electrode participates in the reaction.
Hence, different products are obtained for electrolysis in the case of reactive and inert electrodes. Oxidizing and reducing species present in the electrolytic cell and their standard electrode potential too, affect the products of electrolysis.
FAQs
1. What’s a Faraday?
Ans: The Faraday is an electric charge volume unit without measurements, equal to approximately 6.02 x 10 23 electric charge carriers.
2. Why is Faraday’s law important?
A shifting magnetic flux creates an electric field, according to Faraday’s law. Faraday’s law is particularly important since it addresses the connection of the E-field and the B-field and understands that this connection necessitates flux fluctuation over time.
3. How does electrolysis remove rust?
Ans: Electrolysis is a method of removing iron oxide by passing a small electrical charge through the rusty metal from a battery or battery charger to induce ion exchange while the device is submerged in an electrolyte solution.
4. What happens to water during electrolysis?
Ans: Water’s Electrolysis. By passing an electrical current through it, water can be decomposed. When this happens, an oxidation-reduction reaction is caused by the electrons from the electric current.
5. What is the negative electrode called in electrolysis?
Ans: Through electrolysis, the negatively charged electrode is called the cathode. The positively charged electrode is called the anode in electrolysis. Negatively charged ions are moving towards the anode.
Hope it helps!
Answer:
Faraday's law states that the absolute value or magnitude of the circulation of the electric field E around a closed loop is equal to the rate of change of the magnetic flux through the area enclosed by the loop.
Explanation:
Hope It Helps!!!
If a substance can be given a chemical formula can be considered to be a(n) __________.
If a substance can be given a chemical formula can be considered to be a(n) compound.
What is a compound?A pure substance made up of two or more different elements combined chemically in a fixed ratio is called a compound.
Compounds are substances composed of different elements bonded chemically; only chemical reactions break the chemical bonds or create new chemical bonds leading a compound to form other substances.
Hence, if a substance can be given a chemical formula can be considered to be a(n) compound.
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How many grams of nitrogen,
N2, would be required to create 9.3
moles ammonia, NH3?
Answer:
Explanation:
Hi there!
N₂+3H₂⇋2NH₃
The molecular mass of NH₃ is 34
The mass of N₂ is 28 and mass of H₂ is 2.
Then,
2 moles of NH₃ is created by 28 g of N₂
1 moles of NH₃ is created by 28/2 g of N₂
9.3g of NH₃ is created by (28/2)*9.3 moles of N₂
Therefore, 130.2 g of N₂ is required to create 9.3 moles of NH₃.
Hope it helps!
N₂+3H₂⇔2NH₃
moles N₂ = 1/2 x 9.3 = 4.65
mass N₂ = 4.65 x 28 g/mol = 130.2 g
Please help answer ASAP
How does this evidence indicate that the reaction has occurred between ions? Be specific and explain why the meter readings change throughout the experiment.
The evidence indicate that the reaction has occurred between ions i.e, change of state of the reactants, e.g. precipitation.
What is Precipitation ?In an aqueous solution, precipitation is the process of transforming a dissolved substance into an insoluble solid from a super-saturated solution.
The reaction of the ions can be checked by a number of methods.
In a chemical reaction, the ions are in the acqeuos solution which means that they are in solution, dissolved with charge.
During the reaction (ionic) there is an attraction between the positive and negative ions.
This makes a change in the state of the reactants in the products.
In addition, the reaction can result in an immediate observable change such as the formation of a solid or precipitation.
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How many moles of oxygen gas (02) are
needed to completely react with 54.0 g of aluminum?
4A1+30₂ → 2Al2O3
54.0 g Al
1 mol Al 3 mol O₂
26.98 g Al 4 mol Al
[?] mol O₂
The number of moles of oxygen required to completely react with 54 g of aluminum is 1.5 moles.
Number of moles of the reacting aluminum
moles = reacting mass/molar mass
moles = 54/27
moles = 2 moles
From the given reaction of oxygen and aluminum;
4Al + 30₂ → 2Al₂O₃
4 moles of Al ----------> 3 moles of oxygen
2 moles of AL --------> ? moles of oxygen
= (2 x 3)/4
= 1.5 moles
Thus, the number of moles of oxygen required to completely react with 54 g of aluminum is 1.5 moles.
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A calorimeter absorbs 2,508 J of energy from the snack shown in the data below. How much energy does the snack provide per
gram (J/g) according to the experiment?
The energy provided by the snack is obtained as 1254 J/g.
What is the energy of the snack?The calorimeter is used to measure the energy content of food. The food is burnt in the calorimeter in order to determine the amount of energy that it contains. The mass of the food burnt is converted to energy.
Mass of food burnt = 3.52 g - 1.52 g = 2 g
The energy that is provided by the snack in J/g = 2,508 J/ 2 g
= 1254 J/g
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What is the oxidation state of S in H₂SO4?
OA. +8
OB. +6
OC. -4
OD. -2
Answer:
B.) +6
Explanation:
To find the oxidation number of sulfur, we can assume the oxidation numbers of the other elements.
What I mean is, oxygen (O) always has an oxidation number of (-2). That being said, if there are 4 oxygen atoms, oxygen is contributing -8 overall. We also know that hydrogen generally has an oxidation number of (+1). Like before, if there are 2 hydrogens, it must be contributing +2.
If the overall molecule is neutral, we have to get these charges to balance out.
In essence, -8 + 2 + ? = 0?
If you combine the charges from oxygen and hydrogen, you are left with -6. Therefore, to make the molecule neutral, sulfur must have an oxidation number of +6.
A substance has a melting point of 80 °C. Which of the following is true for the substance? (5 points)
a) It will also change from a liquid to a gas at 80 °C while the liquid loses energy.
b) It will also change from a liquid to a gas at 80 °C while the liquid gains energy.
c) It will also change from a liquid to a solid at 80 °C while the liquid gains energy.
d) It will also change from a liquid to a solid at 80 °C while the liquid loses energy.
Answer:
D
Explanation:
The liquid loses energy while being cooled. It therefore changes to a solid when the liquid is cooled from a temperature above 80°C to 80°C
A substance has a melting point of 80 °C. It will also change from a liquid to a solid at 80 °C while the liquid loses energy and the correct option is option D.
At the substance's melting point of 80 °C, it undergoes a phase transition from a liquid to a solid. During this transition, the substance loses energy to the surroundings as it releases heat to form a solid structure. The process is called solidification or freezing.
As the substance cools down from a higher temperature to 80 °C, its molecules lose kinetic energy, and they arrange themselves into a more ordered and stable lattice, resulting in the formation of a solid. This release of energy is why the liquid loses energy during the transition. Once the substance reaches 80 °C, it remains at this temperature until the entire amount has solidified.
Thus, the ideal selection is option D.
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Please help me solve this questionn as fast as possible oofff
Answer:
sorry I don't know it I'm only 7 th grade
________ is defined as a method of preparing cocaine as a chemical substance so that it can be smoked.
Freebase is defined as a method of preparing cocaine as a chemical substance so that it can be smoked because is is extracted or deduced from the natural source which is plant
What is freebase?Freebase is a that is use while producing cocaine in other to free or extract the base from the natural source which is plant and after which it is grinded into powder so that it can be smoked or sniffed.
Therefore, Freebase is defined as a method of preparing cocaine as a chemical substance so that it can be smoked because is is extracted or deduced from the natural source which is plant
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How do we investigate translocation using tracers?
Translocation can be investigated by using radioactively labelled tracers, which are absorbed into glucose during photosynthesis.
What is translocation?Translocation can be defined as a biological process which involves the transfer (movement) of water and other soluble nutrients from one part of a plant to another, especially through the xylem and phloem.
Generally, translocation can be investigated by using radioactively labelled tracers, which are absorbed into glucose during photosynthesis. Also, an x-ray turns black when exposed to this biological process in plants.
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Consider these two electron configurations for neutral atoms L and M.
L-1s²2s²2p^6 3s²
M-1s²2s²2p^6 3s¹3p¹
What is the atomic number of L?
Calculate electrons
1s²2s²2p⁶3s²[Ne]3s²Total electrons=10+2=12
The element is Magnesium with symbol Mg as atomic no is 12
Additional:-
M:-
1s²2s²2p⁶3s¹3p¹Excited state of magnesium
What is the electron configuration for helium (He)?
O 1s¹
O 1s²
O 1s²2s¹
O 1s²2s²
What is the volume of 0.24 mol oxygen (02) gas at 345 k and a pressure of 0.75
9.06 L is the volume of 0.24 mol oxygen (02) gas at 345 k and a pressure of 0.75.
What is an ideal gas equation?The ideal gas law (PV = nRT) relates to the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
We know that the ideal gas equation relates the pressure, volume, temperature, and moles of gases as:
PV =nRT
This is a combined gas law based on other gas law like Boyle's law, Charle's law, Avagadro's law, Gay Lussac's law
P = pressure = 0.75 atm
V = volume = ?
n = moles = 0.24 mol
R = 0.0821 L atm / molK [gas constant]
T = temperature = 345 K
Putting the values
Volume =[tex]\frac{nRT}{ P}[/tex]
Volume = 0.24 X 0.0821 X 345 / 0.75
= 9.06 L
Hence, 9.06 L is the volume of 0.24 mol oxygen (02) gas at 345 k and a pressure of 0.75.
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3
Which statement describes the law of conservation of energy?
O All systems will exchange matter and energy with their surroundings.
O All systems can exchange energy, but not matter, with their surroundings.
Energy cannot be created nor destroyed, but it changes from one form to another.
O Energy is destroyed in most chemical reactions when new products are formed.
Energy cannot be created nor destroyed, but it changes from one form to another. Hence, option C is correct.
What is energy?Energy is the ability to do work.
In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time.
This law means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.
Hence, option C is correct.
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find the relative atomic mass
Answer:
atomic mass = 16 amu
Explanation:
The atomic mass is the total protons and neutrons in an element. The atomic number represents the total number of protons.
In this form, the superscript (raised exponent) represents the mass number/atomic mass. The subscript represents the atomic number. Therefore, if the number (16) is the superscript, this must be your answer.
¹⁶₈Z
-----> 16 = mass number/ atomic mass
-----> 8 = atomic number
If you know the velocity at which an object is moving, which two things do you know about the object's motion?
O speed and direction
O
distance and speed
time and distance
O direction and time
Answer:
speed and direction are the two things
The thermite reaction reacts iron (III) oxide, Fe2O3, with aluminium powder,Al, the form aluminium oxide, Al2O3 and iron, Fe.
A. a student reacted 16.0g of iron with 8.1g of aluminium powder. which of the two reactants is the limiting reagent? Show your working.
B. Calculate the maximum mass of iron of iron that could be formed using these quantities of reactants.
Answer:
This answer assumes that the strated "16.0g of iron" was meant to be 16.0 grams of iron(III) oxide.
Explanation:
To start, the thermite equation must be balanced.
I find:
1Fe2O3 + 2Al = 1Al2O3 + 2Fe
This tells us we need 2 moles of Al for every 1 mole of Fe2O3.
Now calculate the moles of each reactant:
Moles Fe2O3: 16.0 g/159.7 g/mole = 0.100 moles Fe2O3
Moles Al: 8.1 /26.98 g/mole = 0.300 moles Al
The balanced equation says that in order to react all of the Fe2O3 we'd need twice that amount (in moles) of the Al. (0.100 moles Fe2O3)*(2) = 0.200 moles Al.
Which of the two reactants is the limiting reagent?
We have more than enough moles of Al to react with 0.10 moles of Fe2O3. (We have 0.300 moles Al and all we need is 0.200 moles to react with the 0.10 moles of Fe2O3. Fe2O3 is the limiting reagent.
Calculate the maximum mass of iron of iron that could be formed using these quantities of reactants.
The balanced equation tells us that we will obtain 2 moles of Fe for every 1 mole of Fe2O3 consumed. Since Fe2O3 is the limiting reagent, we will assume that it completely reacts. That means 0.1 moles of Fe2O3 is reacted. Since we expect twice that many moles of Fe, we should obtain 0.200 moles of Fe. At 55.85 g/mole, we should obtain:
(0.200 moles Fe)*(55.85 g Fe/mole Fe) = 11.2 grams Fe
The melting points of electrovalent compounds are higher than the melting points of covalent compounds. Why?
Explanation:
There is an electrostatic force holding the electrovalent bonds together and they're usually structured, whereas in covalent, they are usually free and are only held together by a very weak intermolecular force
what's the geometry of sp³ hybridization ~
Answer:
For sp3 hybridized central atoms the only possible molecular geometry is tetrahedral.
what is the sum of the mass of each kind of atoms of elements in the formula of the compound?
The formula mass of a substance is the sum of the average atomic masses of each atom represented in the chemical formula and is expressed in atomic mass units. The formula mass of a covalent compound is also called the molecular mass.
Using the balanced chemical equation, determine the
number of moles of aluminum required to react with 7.53
mol of chlorine.
2Al(s) + 3Cl2(g) -> 2AlCl3(s)
Answer:
5.02 mol
Explanation:
n(Al) : n(Cl)
2 : 3
x : 7.53
3x = 15.06
n(Al) = 5.02mol
Calculate the bond length (in picometers) of a chemical bond between bromine and sulfur.
Bromine—atomic radius: 119 pm; covalent radius: 114 pm; ionic radius: 182 pm.
Sulfur—atomic radius: 109 pm; covalent radius: 102 pm; ionic radius: 184 pm.
The bond length of a chemical bond between bromine and sulfur is 216 picometers.
Explanation:Bromine and sulfur reacts with each other to form Sulfur dibromide.Sulfur dibromide is a covalent compound which means that a chemical bond exist between them is covalent bond.So, for finding a bond length of a covalently bonded compound we need to add the covalent radiuses of the two atoms.Given,
Covalent radius of bromine is 114 pm;
and covalent radius of sulfur is102 pm.
∴ Bond length of the sulfur dibromide= Covalent radius of bromine + covalent radius of sulfur
∴ Bond length = 114 + 102
∴ Bond length = 216 pm.
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Which statement best describes a physical change?
Explanation:
A physical change is one which can be reversed.it also does not produce any new substance.
changes in state such as the melting of a solid, the freezing and vaporization of a liquid as well as changes In shape are examples of physical changes
The theoretical yield of silver was
determined at 241 g Ag through
calculation. Instead, the reaction
generated only 192 g Ag. What is the percent yield of the reaction?
2AgNO3 + Zn → 2Ag + Zn(NO3)2
[?] %
Answer:
79.7%
Explanation:
Percentage yield = (actual yield/theoretical yield)*100%
Therefore percentage yield for this experiment is: [tex]\frac{192}{241} *100%[/tex]%
[tex]= 0.79668*100[/tex]%
Percentage yield = 79.668%
Rounded to 3 significant figures is 79.7%
Hope this helped!
What is the molar concentration of
a solution that contains
5.0 mol HCl in a total volume
of 10.0 L?
Answer:
0.5 M
Explanation:
Molar concentration : M = n/v
n = moles of solute
v = liters of solution
Hence, 5.0 / 10.0 = 0.5 M
Help me please!! Is for my finals!!
Answer:
C.) They have fewer electrons than protons
Explanation:
Charges on ions are determined by the ratio of electrons to protons. Neutral elements have the same number of protons and electrons. Remember: protons have a positive charge and electrons have a negative charge. However, based on the amount of electrons these elements have, some are more or less willing to give up their electrons to participate in ionic bonding. Potassium usually gives up 1 electron because this satisfies the octet rule. By removing this electron, the element has more protons than electrons, giving it an overall +1 charge.
Atom is a smallest particle of an element which have all the chemical properties of that element.What is the origin of Atom.
Answer:
ORIGIN OF ATOM.Sometimes peoples like to say that atom is like a cell in living things,is it true?comment below,letss goo!!
Explanation:
A greek philosopher known as Democritus was the first to consider the idea that matter is made up of small particles ,about 400BC.
Since there was no experimental evidence to support his idea,it was not accepted.
About 2000 years later an English man called John Dalton revived the discussion.He used experimental evidence to support his idea to convince people that matter is made up of particles called atoms.It accepted!.
An English man called John Dalton revived the discussion.He used experimental evidence to support his idea to convince people that matter is made up of particles called atoms.It was accepted ,he conclude the following theories:
Matter is made up of tiny particles called atom which cannot be splitted into simpler substancesAtom cannot be created nor destroyed