Answer:
Matter changes to a plasma state
Explanation:
Plasma is superheated matter, so when matter is heated to the point that electrons are stripped off of atoms forming ionized gas. Palsma comprises over 99% of the observable universe. Plasma is visible in the form of stars, nebulas, and sometimes even auroras.
Answer:
C. Matter changes to a plasma state.
Explanation:
Correct on Edge 2022!!!
Good luck everyone, you got this! Have a great day!
How much acceleration does a 10 kg object have if pushed by a 75 N force?
a = 7.5 m/s²
Explanation:Hi there !
Newton's second law
F = m×a => a = F/m
1 N = 1kg·m/s²
a = (75kg.m/s²)/10kg
= 7.5 m/s²
Good luck !
What does not represent a compound
Answer:
Every combination of atoms is a molecule. A compound is a molecule made of atoms from different elements. All compounds are molecules, but not all molecules are compounds. Hydrogen gas (H2) is a molecule, but not a compound because it is made of only one element.Explanation:
If 550 grams of KClO3 breaks down and produces 175 grams of KCl, how many grams of O2 are produced?
Answer:
215.51 g of O2.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2KClO3 —> 2KCl + 3O2
Next, we shall determine the mass of KClO3 that decomposed and the mass of O2 produced from the balanced equation. This is illustrated below:
Molar mass of KClO3 = 39 + 35.5 + (16×3)
= 39 + 35.5 + 48
= 122.5 g/mol
Mass of KClO3 from the balanced equation = 2 × 122.5 = 245 g
Molar mass of O2 = 16 × 2 = 32 g/mol
Mass of O2 from the balanced equation = 3 × 32 = 96 g
From the balanced equation above,
245 g of KClO3 decomposed to produce 96 g of O2.
Finally, we shall determine the mass of O2 produced by the decomposition of 550 g of KClO3. This can be obtained as follow:
From the balanced equation above,
245 g of KClO3 decomposed to produce 96 g of O2.
Therefore, 550 g of KClO3 will decompose to produce =
(550 × 96)/245 = 215.51 g of O2.
Therefore, 215.51 g of O2 were obtained from the reaction.
Gases A and B are confined to a cylinder and piston and react to form product C. As the reaction occurs, the system loses 1189 J of heat to surroundings. The piston moves downward as the gases react to form a solid. As the volume of the gas decreases under the constant pressure of the atmosphere, the surroundings do 311 J of work on the system. What is the change in the internal energy of the system
Answer:
The change in the internal energy of the system -878 J
Explanation:
Given;
energy lost by the system due to heat, Q = -1189 J (negative because energy was lost by the system)
Work done on the system, W = -311 J (negative because work was done on the system)
change in internal energy of the system, Δ U = ?
First law of thermodynamics states that the change in internal energy of a system (ΔU) equals the net heat transfer into the system (Q) minus the net work done by the system (W).
ΔU = Q - W
ΔU = -1189 - (-311)
ΔU = -1189 + 311
ΔU = -878 J
Therefore, the change in the internal energy of the system -878 J
1. In general, what is meant by the term chemical bond? Name and
describe the 3 principle types of chemical bonds.
Answer: The simplest and most common type is a single bond in which two atoms share two electrons. Other types include the double bond, the triple bond, one- and three-electron bonds, the three-center two-electron bond and three-center four-electron bond. ... Bonds within most organic compounds are described as covalent.
Explanation:
Why doesn't chromic acid oxidize tertiary alcohol?
which material should you use so that the area is cool in terms of temperture O asphalt O red bricks O concrete O soil O
Answer:
red bricks
Explanation:
right on edg 2020
Red bricks should you use so that the area is cool in terms of temperture. Therefore, option B is correct.
What are red bricks used for?Red bricks can be used in the construction of structures such as buildings, foundations, arches, pavement, and bridges. These can also be used for aesthetic purposes such as landscaping, face work, and a variety of other architectural purposes.
Traditional red bricks are saw to be more robust, and structures constructed with them are stronger than hollow block structures.Red brick can be warm, with rust or terracotta undertones. They could also be cool and more burgundy.
Thus, Red bricks should you use so that the area is cool in terms of temperture, option B is correct.
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A 100.00-mL water sample was adjusted to pH 10 and titrated to the calmagite endpoint with 10.87 mL of 0.0125 M EDTA solution. Then the pH of another 100.00-mL water sample was adjusted to pH 12 and titrated with EDTA to the calcon endpoint. In this second titration, 2.63 mL of titrant was required. Calculate the concentration of Mg2 and Ca2 in the water. Express your answers in mg/L of CaCO3 and MgCO3, respectively.
Answer:
The mass of Ca²⁺ present in the water sample = 13.23 mg/L.
The mass for the Mg²⁺ in the water sample = 25.06 mg/L.
Explanation:
We are given the following set of values which are going to aid in solving this particular question/problem. Thus, the parameters or data or information is given below:
First part:
Total volume of the water sample = 100.00-mL water sample, volume of the EDTA solution = 10.87 mL, the concentration of the EDTA solution = 0.0125 M, the adjusted pH of the water sample with = 10.
Second part:
Total volume of the water sample = 100.00-mL water sample, volume of the EDTA solution = 2.63 mL and the adjusted pH of the water sample with = 12.
Thus, the first thing to do now is to determine the number of moles of the EDTA solution in Ca²⁺ titration which is; 0.0125 x 0.00263 = 3.30 x 10⁻⁵ moles.
The mass of Ca²⁺ present in the water sample = [3.30 x 10⁻⁵ moles × 40.08 ] ÷ 100 mL. = 13.23 mg/L
In 100mL, the number of moles of Mg²⁺ = (total number of moles of EDTA solution used ) - ( number of moles of the EDTA solution in Ca²⁺ titration).
Also, The number of moles of Mg²⁺ = ( 0.0125 x 0.01087) - (3.30 x 10⁻⁵ moles.) = 1.031 x 10⁻⁴ moles.
The mass for the Mg²⁺ in the water sample = 1.031 x 10⁻⁴ moles x 24.305/0.1 = 25.06 mg/L.
9th grade science need help ASAP
Answer:
D
Explanation:
It is a solid everything that is a solid is heavier
What does wadding do?
Answer:
Wadding is a disc of material used in guns to seal gas behind a projectile or to separate powder from shot. ... Wadding for muzzleloaders is typically a small piece of cloth, or paper wrapping from the cartridge.
Explanation:
Why do silver and copper have similar properties? (science CER)
Answer:Copper is a chemical element with the atomic number 29, and the chemical symbol Cu. Silver is also found on the periodic chart of elements, and has a chemical symbol of Ag and an atomic number of 47.
Explanation:
Both silver and copper are transition metals of d-block in periodic table they are in the same group and thus shows similar chemical and physical properties.
What is group in periodic table?In periodic table, elements are classified into groups and periods. The horizontal rows are called periods and the vertical columns are called groups.
There are 18 groups and 7 periods in periodic table. Elements of the same group have same number of valence electrons and similar chemical and physical properties.
Silver, copper and gold are in 11th group of periodic table. Thus they have 9 valence electrons and exhibit similarity in properties. All these metals are good conductors and are used in electrical and optoelectronic devices.
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what is the frequency of light emitted when the electron in a hydrogen atom undergoes a transition from energy level n
Complete question is;
What is the frequency of light emitted when the electron in a hydrogen atom undergoes a transition from energy level n=6 to level n=3?
Answer:
Frequency = 2.742 × 10^(14) s^(-1)
Explanation:
First of all, the energy of hydrogen electron from online values is;
E_n = -2.18 × 10^(-18) × (1/n²) J
n is the principal quantum number
We are told that hydrogen atom undergoes a transition from energy levels n = 3 to n = 6.
Thus, it means we have to find the difference between the electrons energy in the energy levels n = 3 to n = 6.
Thus;
E_n = E_6 - E_3
Thus;
E_n = [-2.18 × 10^(-18) × (1/6²)] - [-2.18 × 10^(-18) × (1/3²)]
E_n = (2.18 × 10^(-18)) × [-1/36 + 1/9]
E_n = 0.1817 × 10^(-18) J
From Planck expression, we can find the frequency. Thus;
E = hf
Where h is Planck's constant = 6.626 × 10^(-34) m²kg/s
Thus;
0.1817 × 10^(-18) = 6.626 × 10^(-34) × f
f = (0.1817 × 10^(-18))/(6.626 × 10^(-34))
f = 2.742 × 10^(14) s^(-1)
What does reflection mean?
Answer:
the throwing back by a body or surface of light, heat, or sound without absorbing it.
"the reflection of light"
Explanation:
i hope this helps
A beam of electrons (m = 9.11 × 10-31 kg/electron) has an average speed of 1.9 × 108 m/s. What is the wavelength of electrons having this average speed, in picometers?
Answer:
12 pm
Explanation:
Step 1: Given data
Mass of an electron (m): 9.11 × 10⁻³¹ kgAverage speed of an electron (v): 1.9 × 10⁸ m/sSpeed of light (c): 3.00 × 10⁸ m/sPlanck's constant (h): 6.63 × 10⁻³⁴ J.sWavelength of an electron (λ): ?Step 2: Calculate the kinetic energy (E) of an electron
We will use the following expression.
E = 1/2 × m × v²
E = 1/2 × 9.11 × 10⁻³¹ kg × (1.9 × 10⁸ m/s)²
E = 1.6 × 10⁻¹⁴ J
Step 3: Calculate the wavelength of an electron
We will use the following expression.
E = h × c / λ
λ = h × c / E
λ = 6.63 × 10⁻³⁴ J.s × 3.00 × 10⁸ m/s / 1.6 × 10⁻¹⁴ J
λ = 1.2 × 10⁻¹¹ m
Step 4: Convert "λ" to picometers
We will use the relationship 1 m = 10¹² pm.
1.2 × 10⁻¹¹ m × (10¹² pm/1 m) = 12 pm
The wavelength of the beam of electrons is 3.8 pm.
Using the De Broglie relation;
λ = h/mv
λ = wavelength
h = Plank's constant
m = mass of the object
v = speed of the object
Now;
λ = ?
h = 6.6 × 10^-34 Js
m = 9.11 × 10^-31 kg
v = 1.9 × 10^8 m/s
So;
λ = 6.6 × 10^-34 Js/ 9.11 × 10^-31 kg × 1.9 × 10^8 m/s
λ = 6.6 × 10^-34 /1.73 × 10^-22
λ = 3.8 × 10^- 12 m or 3.8 pm
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What happens when the elements in group 2 react with iodine
Answer:
Yah
Explanation:
pencil has a density of 14.5 g/mL and a volume of 5 mL. Calculate the mass in grams.
Answer:
The answer is 72.5 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question we have
mass = 14.5 × 5
We have the final answer as
72.5 gHope this helps you
Please help I need to turn this in already
Answer:
The acceleration will be .5 and the force will be 37.5
Have a nice day! :)
Answer:
Hello. The answer is 37.5N.
Explanation:
If you look carfully ، every time that you add one weight the force changes 2.5N so you can do this:
[tex](2.5 \times 5) + 25 = 37.5[/tex]
When aqueous solutions of AgNO3 and KI are mixed, AgI precipitates. The balanced net ionic equation is ________. When aqueous solutions of AgNO3 and KI are mixed, AgI precipitates. The balanced net ionic equation is ________. AgNO3 (aq) + KI (aq) → AgI (s) + KNO3 (aq) Ag+ (aq) + I- (aq) → AgI (s) AgNO3 (aq) + KI (aq) → AgI (aq) + KNO3 (s) Ag+ (aq) + NO3 - (aq) → AgNO3 (aq) Ag+ (aq) + NO3 - (aq) → AgNO3 (s)
Answer:
Ag⁺ (aq) + I¯ (aq) —> AgI (s)
Explanation:
We'll begin by writing the dissociation equation for aqueous AgNO₃ and KI.
Aqueous AgNO₃ and KI will dissociate in solution as follow:
AgNO₃ (aq) —> Ag⁺(aq) + NO₃¯ (aq)
KI (aq) —> K⁺(aq) + I¯(aq)
Aqueous AgNO₃ and KI will react as follow:
AgNO₃ (aq) + KI (aq) —>
Ag⁺(aq) + NO₃¯ (aq) + K⁺ (aq) + I¯(aq) —> AgI (s) + K⁺ (aq) + NO₃¯ (aq)
Cancel out the spectator ions (i.e ions that appears on both sides of the equation) to obtain the net ionic equation. The spectator ions are K⁺ and NO₃¯.
Thus, the net ionic equation is:
Ag⁺ (aq) + I¯ (aq) —> AgI (s)
The net ionic equation of aqueous solutions of [tex]AgNO_3[/tex] and [tex]KI[/tex] to form [tex]AgI[/tex] precipitates is: B. [tex]Ag^{+}_{(aq)} + I^{-}_{(aq)}[/tex] -----> [tex]AgI_{(s)}[/tex]
A balanced chemical equation can be defined as a chemical equation wherein the number of atoms on the reactant (left) side is equal to the number of atoms on the product (right) side.
This ultimately implies that, both the charge on each atom and sum of the masses of the chemical compounds or elements in a chemical equation are properly balanced.
An ion can be defined as an atom or molecules (group of atoms) that has lost or gained one or more of its valence electrons, thereby, making it have a net positive or negative electrical charge.
First of all, we would write the dissociation equation for aqueous solutions of [tex]AgNO_3[/tex] and [tex]KI[/tex]:
For [tex]AgNO_3[/tex]:
[tex]AgNO_3_{(aq)}[/tex] -----> [tex]Ag^{+}_{(aq)} + NO_{3}^{-}_{(aq)}[/tex]
For [tex]KI[/tex]:
[tex]KI_{(aq)}[/tex] -----> [tex]K^{+}_{(aq)} + I^{-}_{(aq)}[/tex]
Next, we would write a chemical equation for the reaction of aqueous solutions of [tex]AgNO_3[/tex] and [tex]KI[/tex]:
[tex]AgNO_3_{(aq)} + KI_{(aq)}[/tex] -----> [tex]Ag^{+}_{(aq)} + NO_{3}^{-}_{(aq)}[/tex] [tex]+ \;K^{+}_{(aq)} + I^{-}_{(aq)}[/tex] ----->[tex]AgI_{(s)} + K^{+}_{(aq)} + NO_{3}^{-}_{(aq)}[/tex]
Note: Spectator ions refers to the ions that exist as a reactant and a product in a chemical equation because they are unchanged by the chemical reaction.
In this chemical reaction, the spectator ions are:
[tex]K^+[/tex][tex]NO_{3}^{-}[/tex]Finally, in order to obtain the net ionic equation, we would cancel out the two (2) spectator ions:
[tex]Ag^{+}_{(aq)} + I^{-}_{(aq)}[/tex] -----> [tex]AgI_{(s)}[/tex]
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2) (3 pts) Convert 85 oF to oC.
Answer:
The answer will be 29.4˚C.
Explanation:
Using the formula 5(˚F-32)/9, plug in the numbers and you'll get 29.4˚C.
Physical and chemical changes occur all around you every day. Read the story below and use the movable
highlighter pieces to highlight the physical changes in PURPLE and the chemical changes in ORANGE.
The physical changes are:
"blend up a banana smoothie instead"."cut a piece of bread in half"."I cracked two eggs and whipped them with a fork"."water had evaporated"."glass breaking"."Steam was rolling out"."broke off a piece"."the chocolate melted".The chemical changes are:
"the milk had soured"."was covered in brown spots"."it was completely tarnished"."plants were dying"."toast must be burning"."rusted bicycle".Changes of matterMatter can undergo 2 kinds of changes:
Physical changes: matter changes form but not its identity.Chemical changes: matter changes its identity due to a chemical reaction.Let's consider the following text.
When my alarm went off at 70'clock, I hit snooze" a few times then finally got out of bed with excitement for my morning bowl of cereal. I poured the cereal and milk into my bowl. But before I even drank it, I could tell from the smell that the milk had soured! So, I decided to blend up a banana smoothie instead. I took some ice out of the freezer and grabbed the only banana that we had in the kitchen, which was covered in brown spots. My grumbling stomach needed to be satisfied before school so I didn't really care.
Just as I was sitting down to drink my smoothie my little brother came bounding into the kitchen and asked, Would you make some eggs and toast for me for breakfast?
"Ugh, sure," I said. I cut a piece of bread in half and put it in the toaster, then I cracked two eggs and whipped them with a fork. I reached for one of my mother's copper cooking pans in the cabinet and saw that it was completely tarnished! I didn't want to be blamed for this, so I ran to tell my mother right away. As I ran out of the kitchen slipped on that banana peel and it smeared all over the floor. As I lay on the floor with the wind knocked from me, I noticed that our family's plants were dying and that some water had evaporated from our fish tank. I made a mental note to take care of these things after school.
Just as I regained my breath and stood up, I heard glass breaking upstairs and my mother shrieking. I ran up the stairs, breathing heavily now. Steam was rolling out from the open bathroom door. When the steam cleared, saw why my mother had been screaming. Before me was my older sister standing in the bathroom with purple hair. I inferred from the scene that my mother had dropped a glass when she first saw her look what your sister did to her hair my mother yelled furiously I decided that I needed to get out of the house immediately, this morning was a crazy one!
A distinct smell was waiting up the stairway and I realized that my brother's toast must be burning! When reached the kitchen, my brother was happily spreading butter on his very browned toast. "I like my toast really crispy!" he said.
"Good I can't handle any more chaos this morning! I exclaimed. I grabbed my backpack headed out into the foggy morning air, and hopped on my slightly rusted bicycle to ride to school. A few minutes into my ride, my stomach grumbled and I realized that I never got a chance to drink my banana smoothie. Luckily, I had stashed a chocolate bar in my backpack yesterday. "Yes! I thought as I stopped pedaling, grabbed the chocolate and broke off a piece. As the chocolate melted in my mouth, I knew that my day was bound to get better!
The physical changes are:
"blend up a banana smoothie instead"."cut a piece of bread in half"."I cracked two eggs and whipped them with a fork"."water had evaporated"."glass breaking"."Steam was rolling out"."broke off a piece"."the chocolate melted".The chemical changes are:
"the milk had soured"."was covered in brown spots"."it was completely tarnished"."plants were dying"."toast must be burning"."rusted bicycle".Learn more about physical and chemical changes here: https://brainly.com/question/17384175
Aspirin is a weak organic acid whose molecular formula is HC9H7O4. An aqueous solution of aspirin is prepared by dissolving 3.60 g/L. The pH of this solution is found to be 2.6. Calculate Ka for aspirin. (atomic mass: C
Answer:
Ka = 3.50x10⁻⁴
Explanation:
First, we need to convert the unit of 3.60 g/L to mol/L:
[tex] C_{C_{9}H_{8}O_{4}} = 3.60 \frac{g}{L}*\frac{1 mol}{180.16 g} = 0.0200 mol/L [/tex]
The reaction dissociation of aspirin in water is:
C₉H₈O₄ + H₂O ⇄ C₉H₇O₄⁻ + H₃O⁺
0.02 - x x x
The constant of the above reaction is:
[tex] Ka = \frac{[C_{9}H_{7}O_{4}^{-}][H_{3}O^{+}]}{[C_{9}H_{8}O_{4}]} [/tex]
[tex] Ka = \frac{x^{2}}{0.02 - x} [/tex]
To find Ka we need to find the value of x. We know that pH = 2.6 so:
[tex] pH = -log[H_{3}O^{+}] [/tex]
[tex] 2.6 = -log(x) [/tex]
[tex] x = 2.51 \cdot 10^{-3} M = [H_{3}O^{+}] = [C_{9}H_{7}O_{4}^{-}] [/tex]
Now, the concentration of C₉H₈O₄ is:
[tex] C_{C_{9}H_{8}O_{4}} = 0.02 - 2.51 \cdot 10^{-3} = 0.018 M [/tex]
Finally, Ka is:
[tex] Ka = \frac{[C_{9}H_{7}O_{4}^{-}][H_{3}O^{+}]}{[C_{9}H_{8}O_{4}]} = \frac{(2.51 \cdot 10^{-3})^{2}}{0.018} = 3.50 \cdot 10^{-4} [/tex]
Therefore, the Ka of aspirin is 3.50x10⁻⁴.
I hope it helps you!
Which statements about mixture is FALSE?
A. The ingredients ofvthe mixture keep their physical properties
B. Mixture components can be separated
C. All mixtures are food or drink only
D. A mixture contains more than one ingredients
Which of the items below is a colloid?
a.fruit salad b.gelatin c.lacquer
Answer:
b. gelatin
Explanation:
a homogeneous noncrystalline consisting of large molecules or ultramicroscopic particles of one substance.
it is the main factor of contact metamophism.
Answer:
The size of a contact aureole depends on a number of factors that control the rate at which heat can move out of the pluton and into the surrounding country rock. Among these factors are: The size and temperature of the intrusion. This will control how much heat is available to heat the surrounding country rocks
Explanation:
Hope this helps u
crown me as brainliest
When you finish exercising, you are hot, tired, and sweating. After a bottle of juice, you feel a lot better. Which organ systems are working together in this scenario?
Answer:
Nervous and Excretory
Explanation:
The nervous system makes you thirsty. The integumentary system makes you sweat. the integumentary system is very similar to the Excretory system.
Nervous and Excretory systems are working together in this scenario.
The nervous system makes you thirsty. The integumentary system makes you sweat. the integumentary system is very similar to the Excretory system.
The blood flow increases, your brain is exposed to more oxygen and nutrients. Exercise also induces the release of beneficial proteins in the brain. Sweating cools the body when it becomes warm. When the body temperature rises, such as when exercising on a hot day, the dermal blood vessels dilate.The excretory system works with the endocrine system to help maintain homeostasis.Learn more:
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A. In a separatory funnel containing ethyl acetate and 10% aqueous sodium bicarbonate (NaHCO3), which layer would contain the brominated aromatic compound?
Answer:
ethyl acetate layer
Explanation:
This question tests your knowledge of the principle of solvent extraction.
In solvent extraction, there is always an organic layer and an aqueous layer. The ethyl acetate is the organic layer while the sodium bicarbonate is the aqueous layer.
A brominated aromatic compound will be extracted into the organic layer (ethyl acetate layer).
Many scientists have contributed to the atomic theory. In 1803 John Dalton gave new insight to this theory. Which desciption of an atom fits our most
current understanding?
Fyry nyyden atom is the same as every hydrogen atom
help pls
Which process of sedimentary rock formation occurs last?
cementation
compaction
deposition
erosion
Answer:
Compaction.
Explanation:
All the others are before this.
For the combustion of methane presented in Example 5.4, the chemical reaction is CH4 +2O2 →CO2 +2H2O Suppose that methane flows into a burner at 30 gmol/s, while oxygen flows into the same burner at 75 gmol/s. If all the meth- ane is burned and a single output stream leaves the burner, what is the mole fraction of CO2 in that output stream? Hint 1: Does the fact that all the methane is burned mean that all the oxygen is burned also? Hint 2: Find the molar flow rate of each component gas in the outlet gas ("flue gas").
Answer:
[tex]x_{CO_2}^{out} =0.25[/tex]
Explanation:
Hello.
In this case, for the reactive scheme, it is very convenient to write each species' mole balance as shown below:
[tex]CH_4:f_{CH_4}^{out}=f_{CH_4}^{in}-\epsilon \\\\O_2:f_{O_2}^{out}=f_{O_2}^{in}-2\epsilon\\\\CO_2:f_{CO_2}^{out}=\epsilon\\\\H_2O:f_{H_2O}^{out}=2\epsilon[/tex]
Whereas [tex]\epsilon[/tex] accounts for the reaction extent. However, as all the methane is consumed, from the methane balance:
[tex]0=f_{CH_4}^{in}-\epsilon \\\\\epsilon=30gmol/s[/tex]
Thus, we can compute the rest of the outlet mole flows since not all the oxygen is consumed as it is in excess:
[tex]f_{O_2}^{out}=f_{O_2}^{in}-2\epsilon=75gmol/s-2*30gmol/s=15gmol/s\\\\f_{CO_2}^{out}=15gmol/s\\\\f_{H_2O}^{out}=2*15gmol/s=30gmol/s[/tex]
It means that the mole fraction of carbon dioxide in that output is:
[tex]x_{CO_2}^{out}=\frac{15}{15+15+30} =0.25[/tex]
Best regards.
When 2.16g of H2 reacts with excess O2 by the following equation, 258 kJ of heat are released. What is the change of enthalpy associated with the reaction of 1.00 mol of hydrogen gas? 2H2+O2⟶2H2O
Answer:
-241 kJ/mol
Explanation:
Let's consider the reaction of hydrogen with excess oxygen to form water.
2 H₂ + O₂ ⟶ 2 H₂O
When 2.16g of hydrogen reacts with excess oxygen, 258 kJ of heat are released, that is, Q = -258 kJ. Considering that the molar mass of hydrogen is 2.02 g/mol, the change of enthalpy associated with the reaction of 1.00 mol of hydrogen gas is:
ΔH° = -258 kJ/2.16 g × (2.02 g/1.00 mol) = -241 kJ/mol