Answer:
The chemical name ends with “hydroxide.”
Explanation:
1- we write the name of the metal first and after that write the nonmetal:
Ex : NaOH ( sodium hydroxide)
2- any compound contains OH group is an ionic base and this group called hydroxide group
3- "Ous" ending is given in the ions with the lower oxidation.
4- " ic" ending is given in the ions with the higher oxidation.
So, the correct answer is: The chemical name ends with “hydroxide.”.
Answer:
The chemical name ends with “hydroxide
Explanation:
got right on edge 2020
Choose the number of significant figures indicated 0.06
Answer:
2
Explanation:
What is true of acids?
a.They are poor electrolytes.
b.They have a pH above 9.
c.They have a pH below 7.
d.They have a strong affinity for H ions.
Acids have a pH below 7 (option c), indicating a higher concentration of hydronium ions.
The correct answer is: c. They have a pH below 7.
In chemistry, acids are substances that have a pH value lower than 7. This lower pH indicates a higher concentration of hydronium ions (H₃O⁺) compared to pure water. For example, vinegar, which tastes sour, is an acid with a pH lower than 7. Strong acids are particularly notable for being able to damage materials, demonstrating their high acidity.
Here's why the other options are incorrect:
a. They are poor electrolytes.: Acids are actually good electrolytes, meaning they can conduct electricity in a solution. This is because they dissociate into ions, such as H+ and anions, which can carry electrical charge.b. They have a pH above 9.: This is actually characteristic of bases, not acids. Bases have a pH above 7, with a higher pH indicating a stronger base.d. They have a strong affinity for H ions.: This statement is somewhat misleading. Acids do release H+ ions, but they don't have a strong affinity for them. Instead, acids tend to donate H+ ions, increasing their concentration in a solution.as electrons pass through a particular device magnets begin to rotate. this rotation is then used to power devices such as ceiling fans this is a description of what happens in a what
Answer:
Motor
Explanation:
This actuation of electric energy to mechanical energy is due to reverse magnetic induction. When you pass a wire coil, with electricity passing through it, along a magnetic field, the coil will rotate according to Fleming’s Left Hand Hand Rule. This principle is harnessed in the making of motors that can be used to power equipments such as fans.
Answer:
D) electric motor
Explanation:
Thats the answer for apex. A) electric generator B) power surge C) battery D) electric motor
Need help on this ASAP !!!!
Answer:
0.1612 mol.
Explanation:
From the balanced equation:2Ca₃(PO₄)₂ + 6SiO₂ + 10C → 6CaSiO₃ + P₄ + 10CO.
2.0 moles of Ca₃(PO₄)₂ react with sufficient SiO₂ and C to produce 1.0 mole of P₄ and other products.
we need to calculate the no. of moles of 100.0 g of Ca₃(PO₄)₂:no. of moles of Ca₃(PO₄)₂ = mass / molar mass = (100.0 g)/(310.18 g/mol) = 0.3224 mol.
Using cross-multiplication:
2.0 moles of Ca₃(PO₄)₂ produce → 1.0 mole of P₄.
0.3224 mole of Ca₃(PO₄)₂ produce → ??? mole of P₄.
∴ The no. of moles of phosphorous (P₄) will be produced = (1.0 mole)(0.3224 mole)/(2.0 mole) = 0.1612 mol.
3AI²O³ What is the name of the element
Answer:
Aluminium oxide
Explanation:
This is not an element but a coumpound.
Al is Aluminum
And O is Oxygen
Animals need food air and water.which of the following is another need of animals
Answer:
a habitat
Explanation:
The correct answer is shelter and their right climate is another need of animals.
What are some of the animals' most basic requirements?Animals have four essential needs: air, water, food, and shelter. Living creatures have the following basic requirements: Sunlight: Because it is the source of all energy, this is undoubtedly the most important need for all living species.Learn more about the basic needs of animals here:-
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What does Hund's rule state?
Answer:
Explanation:
Hund's Rule of Maximum Multiplicity states that electrons go into degenerate orbitals of sub-orbitals(p, d and f) singly before pairing commences.
Hund's rule is useful in determining the number of unpaired electrons in an atom. Hence, it explains some of the magnetic properties of elements.
An element whose atoms or molecules contain unpaired electrons is paramagnetic.
The element whose atoms or molecules contain orbitals that are all filed up with paired electron is diamagnetic.
Hund's rule states that in degenerate orbitals, electrons must occupy orbitals singly and with parallel spins before pairing up. This ensures the lowest-energy electron configuration. A common example is seen in the p orbitals for nitrogen.
Hund's Rule
Hund's rule states that the lowest-energy electron configuration for an atom is the one that has the maximum number of electrons with parallel spins in degenerate orbitals. This means that in any given sub-level other than the s orbital, electrons will occupy each orbital singly before starting to pair up. For instance, in the p sublevel, which has three degenerate orbitals, each of these orbitals will get one electron before any one of them gets a second electron with the opposite spin.
An easy way to visualize this is by considering the p orbitals (px, py, and pz) for an atom like nitrogen, which has three electrons in its p sublevel. According to Hund's rule, each of these three electrons will occupy one of the p orbitals singly, with parallel spins, resulting in a more stable and lower-energy configuration.
Elizabeth is getting ready to run a marathon why is her thinking incorrect
Answer:
Oh, I don't run
Explanation:
Alex Russo
Elizabeth is getting ready to run a marathon, her thinking incorrect due to lack of training and unrealistic Expectations.
Lack of Training: Marathon runners need to be properly trained and condition themselves. Elizabeth's reasoning can be flawed if she hasn't had enough training since she might underestimate the physical difficulties and the risks involved in the marathon. Without adequate training, she can experience fatigue, injuries, or other health problems while competing.
Elizabeth might have exaggerated expectations on how well she will perform in the marathon. She would be mistaken in her reasoning, for instance, if she thought she could run the marathon in a relatively short amount of time without any training or prior experience. Setting reasonable objectives that take into account one's ability and level of fitness is crucial.
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Using the concentration of the base and the volume of the base used, calculate the moles of the base used in the titration. Then, using the mass of the acid, determine the molar mass of the acid.
Data:
Concentration of the Base(NaOH)= 0.19 M
Volume of the Base used= 8.72 mL
Mass of the Acid(unknown)= 0.33 g
Answer:
[tex]\boxed{\text{(a) 0.001 66 mol MOH; (b) 200 g/mol}}[/tex]
Explanation:
I am assuming that the unknown acid is monobasic. Then the general equation for the reaction is
HA + MOH ⟶ MA + H₂O
(a) Moles of MOH
[tex]\text{Moles of MOH}= \text{0.008 72 L MOH} \times \dfrac{\text{0.19 mol MOH}}{\text{1 L MOH}} = \text{0.001 66 mol MOH}[/tex]
(b) Moles of HA
Now, you use the molar ratio from the balanced chemical equation to find the moles of unknown acid.
[tex]\text{Moles of HA = 0.001 66 mol MOH} \times \dfrac {\text{1 mol HA}}{\text{1 mol MOH }} = \text{0.001 66 mol HA}[/tex]
(c) Molar mass of HA
[tex]\text{MM} =\dfrac{\text{mass}}{\text{moles}}= \dfrac{\text{0.33 g}}{\text{0.001 66 mol}} = \text{200 g/mol}[/tex]
The molar mass of the unknown acid is [tex]\boxed{\textbf{200 g/mol}}[/tex]
13. A gas occupies 4.31 liters at a pressure of 0.755 atm. Determine the volume if the
pressure
is increased to 1.25 atm.
14. 600.0 mL of a gas is at a pressure of 8.00 atm. What is the volume of the gas at 2.00
t
.
Answer:
13. 2.60 L.
14. 2.40 L.
Explanation:
We can use the general law of ideal gas: PV = nRT.
where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
If n and T are constant, and have different values of P and V:
(P₁V₁) = (P₂V₂)
13. A gas occupies 4.31 liters at a pressure of 0.755 atm. Determine the volume if the pressure is increased to 1.25 atm.
P₁ = 0.755 atm, V₁ = 4.31 L.
P₂= 1.25 atm, V₂ = ??? L.
∴ V₂ = (P₁V₁)/(P₂) = (0.755 atm)(4.31 L)/(1.25 atm) = 2.60 L.
14. 600.0 mL of a gas is at a pressure of 8.00 atm. What is the volume of the gas at 2.00 at m.
P₁ = 8.0 atm, V₁ = 600.0 mL.
P₂= 2.0 atm, V₂ = ??? L.
∴ V₂ = (P₁V₁)/(P₂) = (8.0 atm)(600.0 mL)/(2.0 atm) = 2400/0 mL = 2.40 L.
Using Boyle's law, which states that the pressure and volume for a gas is a constant if the temperature is constant, we can determine that the new volume of the gas occupying 4.31 liters at 0.755 atm when the pressure is increased to 1.25 atm is 2.62 L. Similarly, when the pressure of a gas occupying 600.0 mL at 8.00 atm is reduced to 2.00 atm the new volume will be 2400 mL.
Explanation:To solve these problems, we can use the principles of Boyle's law, which states that the product of the pressure and volume for a gas is a constant if the temperature and the amount of gas remain unchanged. In other words, P1*V1 = P2*V2.
Problem 13
Let's use Boyle's law to calculate the new volume (V2) when the pressure (P2) is increased to 1.25 atm (P2). We know that the initial volume (V1) is 4.31 L, and the initial pressure (P1) is 0.755 atm.
V2 = P1*V1/P2 = (0.755 atm * 4.31 L) / 1.25 atm = 2.62 L
Problem 14
The initial volume (V1) is 600 mL and the initial pressure (P1) is 8.00 atm. The new pressure (P2) is 2.00 atm. So, we can calculate the new volume (V2) as:
V2 = P1*V1/P2 = (8.00 atm * 600.0 mL) / 2.00 atm = 2400 mL
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What kind of system is the carbon cycle
Answer:
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth.
The carbon cycle is a biological and geological system composed of two interconnected sub-cycles - the biological carbon cycle and the biogeochemical carbon cycle. The biological carbon cycle involves the exchange of carbon among living organisms through processes like photosynthesis and respiration, while the biogeochemical carbon cycle involves the long-term cycling of carbon through the Earth's atmosphere, water bodies, and interior. Human activities like burning of fossil fuels can accelerate these cycles and contribute to global climate change.
Explanation:The carbon cycle is a type of system in biology that can be broadly divided into two interconnected sub-cycles. One sub-cycle deals with the rapid exchange of carbon among living organisms, and the other deals with the long-term cycling of carbon through geologic processes. These processes together help in the transfer and recycling of carbon in different forms throughout the ecosystem.
In the Biological Carbon Cycle, living organisms play a crucial role. Autotrophs, like plants, absorb carbon dioxide from the atmosphere and convert it into glucose through photosynthesis. This glucose is used by heterotrophs, like animals, for their energy needs. In this process, carbon gets incorporated in their bodies. When these animals die, the carbon gets returned to the atmosphere through decomposition. Moreover, marine autotrophs obtain carbon dioxide in the dissolved form (carbonic acid, H₂CO3). Through this biological carbon cycle process, photosynthetic organisms are responsible for maintaining approximately 21 percent of the Earth's oxygen content.
In the Biogeochemical Carbon Cycle, carbon is stored in what are known as carbon reservoirs that include the atmosphere, bodies of liquid water (mostly oceans), ocean sediment, soil, land sediments (including fossil fuels), and the Earth's interior. Over longer periods, microorganisms capable of digesting non-bioavailable carbon like coal can release it as gas, making it available for other living organisms. This process accelerates when humans burn fossil fuels, releasing large amounts of carbon dioxide into the atmosphere. Most scientists agree that the high atmospheric carbon dioxide is a major cause of global climate change.
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what kind of bond is ca-br
Final answer:
The bond between calcium (Ca) and bromine (Br) is an ionic bond, where calcium donates electrons to form Ca2+ ions, and bromine atoms each gain an electron to form Br- ions, creating an ionic compound.
Explanation:
The bond between calcium (Ca) and bromine (Br) in the compound CaBr2 is an ionic bond. This type of bond is formed when one atom (in this case, calcium) donates one or more electrons to another atom (in this case, bromine).
Calcium is a metal with a tendency to lose electrons and form a positive ion (Ca2+), while bromine is a non-metal with a tendency to gain electrons and form a negative ion (Br−).
When calcium gives up two electrons, one for each bromine atom, each bromine atom gains one electron, resulting in two Br− ions. These oppositely charged ions attract each other, creating an ionic bond.
A fact is something that has been proven to be true.
True
False
i am in a test :/
Answer:
True.
Explanation:
the answer to your question is True !
The image shows information about the element carbon as it appears in the periodic table. Based on the image, how many protons does carbon have?
Answer:6
Explanation:
U welcome
What is the percent composition of silicon in silicon carbide (SiC)? A. 28% B. 50% C. 70% D. 142%
Hey there!
Here goes your answer ↓
Question :- What is the percent composition of silicon in silicon carbide (SiC)?
A. 28%
B. 50%
C. 70%
D. 142%
Answer :- The percentage of silicon content in silicon carbide (SiC) is option (C) 70%.
Hope it helps you.
Have a great day ahead!
Answer : The correct option is, (C) 70%
Explanation : Given,
Molar mass of Si = 28.09 g/mole
Molar mass of C = 12 g/mole
Molecular mass of SiC = 28.09 + 12 = 40.09 g/mole
To calculate the mass percent of an element in a compound, we use the equation:
[tex]\text{Percent composition of Si}=\frac{\text{Mass of Si in compound}}{\text{Mass of the compound}}\times 100[/tex]
Now put all the given values in above equation, we get:
[tex]\text{Percent composition of Si}=\frac{28.09g}{40.09g}\times 100=70\%[/tex]
Hence, the percentage composition of Si in the given compound is 70%
A balloon was partially filled with helium gas at room temperature. It occupied 4.0 liters of volume at 700.0 mmHg atmospheric pressure. When the balloon was released, it traveled upward until it burst at 99 mmHg atmospheric pressure. (Neglect any force exerted to stretch the rubber balloon.) What was the volume of the balloon when it burst? L
Final answer:
To find the volume of the balloon when it burst at 99 mmHg, we use Boyle's Law. The final volume was calculated to be approximately 28.28 liters.
Explanation:
The volume of the balloon when it burst at 99 mmHg atmospheric pressure can be determined using Boyle's Law, which states that the product of pressure and volume is constant for a given mass of enclosed gas when the temperature is constant (P1V1 = P2V2).
Here, we know the initial pressure (P1) is 700.0 mmHg, the initial volume (V1) is 4.0 liters, and the final pressure (P2) upon bursting is 99 mmHg. To find the final volume (V2), we rearrange the equation to V2 = (P1V1) / P2 and substitute the known values. Doing so gives us V2 = (700.0 mmHg × 4.0 L) / 99 mmHg, which calculates to a volume of approximately 28.28 liters.
What is the frequency of light for which the wavelength is 7.1 × 102 nm?
2.4 × 10 −6 s −1
2.1 × 102 s −1
4.2 × 105 s −1
4.2 × 1014 s −1
Answer:
4.2 × 10⁻¹⁴s⁻¹
Explanation:
Given parameters:
Wavelength of light = 7.1 x 10²nm
We simplify and express this value in metres(m) to give:
⇒7.1 x 10² x 10⁻⁹m = 7.1 x 10⁽⁻²⁺⁹⁾ m
= 7.1 x 10⁷m
The wavelength is 7.1 x 10⁷m
We use the formula V = fλ
We know that Velocity of light is 3 x 10⁸ms⁻¹
Making f, frequency the subject of the formula gives :
f = V/λ
f = 3 x 10⁸ms⁻¹ / 7.1 x 10⁷m
f = 4.2 x 10⁻¹⁴s⁻¹
The frequency of light with a wavelength of 7.1 × 10² nm is 4.23 × 10^14 s⁻¹.
Explanation:The frequency of light with a wavelength of 7.1 × 10² nm can be calculated using the formula:
$$ \nu = \frac{c}{\lambda} $$
where c is the speed of light (3.00 × 10^8 m/s) and λ is the wavelength in meters.
Plugging in the values, we get:
$$ \nu = \frac{3.00 \times 10^8 \, \text{m/s}}{7.1 \times 10^{-9} \, \text{m}} = 4.23 \times 10^{14} \, \text{s}^{-1} $$
Therefore, the frequency of light with a wavelength of 7.1 × 10² nm is 4.23 × 10^14 s⁻¹.
During a lunar eclipse, the moon appears to be darkened because _______________ is casting a shadow on it.
the earth
the sun
Mars
Answer:
the earth
Explanation:
because the moon is blocking the light of the sun
If an object moves faster and faster, what must change?
The energy speed!!!!
1. Quartz crystals normally used in quartz clocks etc. is chemically
A. silicon dioxide
B. germanium oxide
C. a mixture of germanium oxide and silicon dioxide
D. sodium silicate
2. Which of the gas is not known as green house gas?
A. Methane
B. Nitrous oxide
C. Carbon dioxide
D. Hydrogen
Answer:
1. A. silicon dioxide
2. D. Hydrogen
Explanation:
From the solubility curve, which salt shows the least change in solubility as the temperature increases?
Answer:NaCl (Sodium Chloride )
Explanation:As it has Solubility 35.7
Answer:
NaCl
Explanation:
When 24g of magnesium metal is heated in air, 40g of magnesium oxide is produced. What mass of magnesium would be needed in order to produce 10g of magnesium oxide?
Final answer:
To produce 10g of magnesium oxide, 6g of magnesium would be needed.
Explanation:
To find the mass of magnesium needed to produce 10g of magnesium oxide, we can use the given information about the reaction between magnesium and oxygen. From the given information, we know that when 24g of magnesium is heated in air, 40g of magnesium oxide is produced. This means that the reaction produces a 1:1 ratio between the mass of magnesium and the mass of magnesium oxide. Therefore, if 24g of magnesium produces 40g of magnesium oxide, then 10g of magnesium oxide would require (10g/40g) * 24g = 6g of magnesium.
Leo's recipe for banana bread won't fit in his favorite pan. The batter fills the 8.5 inch by 11 inch by 1.75 inch pan to the very top, but when it bakes it spills over the side. He has another pan that is 9 inches by 9 inches by 3 inches, and from past experience he thinks he needs about an inch between the top of the batter and the rim of the pan. Should he use this pan? WHY or WHY not? (I posted in chemistry oops)
yes because the
0。5 that's left may stop the batter from over flowing
Identify the following parts of the chemical equation
A:Coefficients B:Element C:subscripts D:Reactants E:Products
What is the empirical formula for sulfur dioxide?
Answer:Sulfur dioxide
CID: 1119
Molecular Formula: SO2 or O2S
UNII:0UZA3422Q4
Chemical Names: sulfur dioxide sulphur dioxide Sulfurous anhydride 7446-09-5 Sulfurous oxide More...
Molecular Weight: 64.058 g/mol
Explanation: can i have brailyest plz
Answer:
SO2
Explanation:
A sample of hydrated copper (II) sulfate has a mass of 4.56 g. After heating, it has a mass of 2.92 g.
What is the percent by mass of water in the hydrate?
Answer:
36.0%.
Explanation:
The mass of water = mass of hydrated copper (II) sulfate - mass of copper (II) sulfate after heating = 4.56 g - 2.92 g = 1.64 g.
The percent by mass of water in the hydrate = (mass of water/mass of hydrated copper (II) sulfate)*100 = (1.64 g/4.56 g)*100 = 35.96% ≅ 36.0%.
The variable that a scientist observes to change while conducting an experiment is called the ___ variable.
A.) mainipulated
B.) responding
C.) independent
Great Question!
The Answer Would Be "B" The "RESPONDING" Variable
The variable that a scientist observes to change while conducting an experiment is called the responding variable.
When 16.3 g of magnesium and 4.52 g of oxygen gas react, how many grams of magnesium oxide will be formed? Identify the limiting and excess reactants.
Answer:
22.77 g.
he limiting reactant is O₂, and the excess reactant is Mg.
Explanation:
From the balanced reaction:Mg + 1/2O₂ → MgO,
1.0 mole of Mg reacts with 0.5 mole of oxygen to produce 1.0 mole of MgO.
We need to calculate the no. of moles of (16.3 g) of Mg and (4.52 g) of oxygen:no. of moles of Mg = mass/molar mass = (16.3 g)/(24.3 g/mol) = 0.6708 mol.
no. of moles of O₂ = mass/molar mass = (4.52 g)/(16.0 g/mol) = 0.2825 mol.
So. 0.565 mol of Mg reacts completely with (0.2825 mol) of O₂.
∴ The limiting reactant is O₂, and the excess reactant is Mg (0.6708 - 0.565 = 0.1058 mol).
Using cross multiplication:
1.0 mole of Mg produce → 1.0 mol of MgO.
∴ 0.565 mol of Mg produce → 0.565 mol of MgO.
∴ The amount of MgO produced = no. of moles x molar mass = (0.565 mol)(40.3 g/mol) = 22.77 g.
Answer:
[tex]m_{MgO}=11.3gMgO[/tex]
Explanation:
Hello,
In this case, the undergoing chemical reaction is:
[tex]2Mg+O_2\rightarrow 2MgO[/tex]
Hence, for given amounts of magnesium and oxygen, one computes the available moles of magnesium with its given mass and atomic mass and the moles of magnesium that will completely react with 4.52 g of oxygen by using their 2:1 molar ratio in the chemical reaction in order to identify the limiting reactant:
[tex]n_{Mg}^{available}=16.3gMg*\frac{1molMg}{24gMg}=0.679molMg\\\\n_{Mg}^{reacted}=4.52gO_2*\frac{1molO_2}{32gO_2}*\frac{2molMg}{1molO_2} =0.2825molMg[/tex]
In such a way, as just 0.2825 moles of magnesium react, magnesium is identified as the excess reactant and the oxygen the limiting reactant. Furthermore, with the reacting moles, one computes the yielded grams of magnesium oxide as:
[tex]m_{MgO}=0.2825molMg*\frac{2molMgO}{2molMg}*\frac{40gMgO}{1molMgO} \\\\m_{MgO}=11.3gMgO[/tex]
Best regards.
What term best describes an underground stem that grows along sending up new plants at intervals
The term for an underground stem that sends up new plants at intervals is a rhizome, while a stem that does this above ground is referred to as a stolon or runner.
The term that best describes an underground stem that grows along, sending up new plants at intervals, is a rhizome. Rhizomes are modified stems that grow horizontally underground and can branch at nodes to produce new plants. A well-known plant that reproduces from rhizomes is the iris. However, if the stem grows above the ground, it's called a stolon or runner, like those seen in strawberry plants. These runners develop adventitious roots at their nodes, and the axillary buds can turn into independent plants.
Another form of modified stem includes corms, which are fleshier and store food, and unlike rhizomes and stolon, don't typically give rise to new plants at intervals along their length.
How many kJ of energy will be released when 4.72g of carbon react with excess oxygen to produce carbon dioxide (delta H is -393.5 kJ)
Answer:
155 kJ of energy will be released.
Explanation:
The [tex]\rm \Delta H\textdegree[/tex] ([tex]\rm \Delta H \textdegree_\text{rxn}[/tex] in some textbooks) here stands for standard enthalpy change per mole reaction. To find the amount of energy released in this reaction, start by finding the number of moles of this reaction that will take place.
How many moles of atoms in 4.72 grams of carbon?
Relative atomic mass data from a modern periodic table:
C: 12.01.[tex]\displaystyle n = \frac{m}{M} = \rm \frac{4.72\;g}{12.01\; g\cdot mol^{-1}} = 0.393006\; mol[/tex].
The coefficient of carbon in the equation is one. In other words, each mole of the reaction will consume one mole of carbon. Oxygen is in excess. As a result, [tex]\rm 0.393006\; mol[/tex] of carbon will support [tex]\rm 0.393006\; mol[/tex] of the reaction.
How much energy will be released?
The [tex]\rm \Delta H\textdegree{}[/tex] value here is negative. But don't panic. [tex]\rm \Delta H\textdegree{}[/tex] is the same as the chemical potential energy of the reactants minus the products in one mole of the reaction. [tex]\rm \Delta H\textdegree{} = -393.5\;kJ[/tex] means that the chemical potential energy drops by [tex]\rm 393.5\; kJ[/tex] during each mole of the reaction (with the coefficients as-is.) Those energy difference will be released as heat. In other words, one mole of the reaction will release [tex]\rm 393.5\;kJ[/tex] of energy.
The 4.72 grams of carbon will support [tex]\rm 0.393006\; mol[/tex] of this reaction. How much heat will that [tex]\rm 0.393006\; mol[/tex] of reaction release?
[tex]Q = n \cdot (-\Delta \text{H}\textdegree{}) = \rm 0.393006\times 393.5 = 155\;kJ[/tex].
As a side note, the mass of carbon 4.72 grams is the least significant data in this question. There are three significant figures in this value. As a result, keep more than three significant figures in calculations but round the final result to three significant figures.
The energy released when 4.72g of carbon reacts with excess oxygen to form CO₂ is -154.8 kJ.
To determine how many kJ of energy are released when 4.72g of carbon reacts with excess oxygen to produce carbon dioxide, we use the given enthalpy change (ΔH) for the reaction:
First, we need to find the number of moles of carbon in 4.72g:
Molar mass of carbon = 12 g/mol
Moles of carbon = mass / molar mass = 4.72 g / 12 g/mol = 0.3933 mol
The reaction for the combustion of carbon to form CO₂ is exothermic, with ΔH = -393.5 kJ/mol.
The total energy released is calculated as follows:
Energy released = moles of carbon x ΔH
Energy released = 0.3933 mol x -393.5 kJ/mol = -154.8 kJ
Thus, the energy released when 4.72g of carbon reacts with excess oxygen is -154.8 kJ.