Answer:
Hof(X) = - 1474.9 KJ/mol
Explanation:
The reaction equation given to us is:
2 X + 5 O2 (g) --> 4 CO2 (g) + 6 H2O (g) ∆H = -75.0 kJ
Now, the equation for the standard enthalpy of formation of the reaction is written as follows:
ΔH = 4*Hof(CO2(g)) + 6*Hof(H2O(g)) - 2*Hof(X) - 5*Hof(O2(g))
where,
ΔH = - 75 KJ
Hof(CO2(g)) = Standard Heat of Formation of CO2(g) = -393.5 KJ/mol
Hof(H2O(g)) = Standard Heat of Formation of H2O(g) = -241.8 KJ/mol
Hof(X) = Standard Heat of Formation of X = ?
Hof(O2(g)) = Standard Heat of Formation of O2(g) = 0 KJ/mol
Therefore,
-75 KJ = (4)(-393.5 KJ/mol)+ (6)(-241.8 KJ/mol) - (2)(Hof (X)) - (5)(0 KJ/mol)
- 75 KJ + 3024.8 KJ = - (2)(Hof(X))
Hof(X) = -2949.8 KJ/2 mol
Hof(X) = - 1474.9 KJ/mol
it can be formed by atoms sharing electrons or by negative and positive
ions joining).. is it mixture or compound ?
Answer:
VVV
Explanation:
Covalent bonds are formed when atoms share electrons and ionic bonds are formed when positive and negative ions bond to form an ionic compound.
Which sentence describes a characteristic of matter
Answer: Matter takes up space and has mass
Explanation:
Literally the definition of mass
Which is a better substitute for water, Li2O or H2S?
Answer:
h2s
Explanation:
The closest chemical analogue for water is hydrogen sulphide or H₂S. Because, both oxygen and sulfur are same group elements and shows similar properties.
What is H₂S?Hydrogen sulphide or H₂S is a covalent compound formed by the combination of two hydrogens and one sulphur atoms. In this compound, each hydrogen shares one electron to sulfur and sulfur shares its two valence electrons to each hydrogen.
Water is H₂O, which is formed by the strong hydrogen bonding between hydrogen and oxygen and it exists as liquid mostly. Most of the compounds can be dissolved in water.
Lithium oxide Li₂O is a covalent compound with partial ionic character and it does not exhibit any similarity with water in any case.
Bothe sulfur and oxygen are in 16th group. They are gases with high electronegativity. Hence, both H₂O, H₂S are polar compounds. Both sulfur and oxygen have affinity towards hydrogen. Both have similar shape and bond angle.
Moreover, H₂S can dissolve some minerals and acts as a good solvent like water.
Hence, the better substitute for water is H₂S.
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why do u think some consumers believe that labortory testing of a product serves as proof of quality?
Answer:
to show that the consumer can use it in a way that the lab cant. with the consumer seeing that the product they're purchasing is good quality can lead to a demand for the product!
Explanation:
based on your observation, you can infer that thermal energy transfers to/from objects with higher temperatures to/from objects with lower temperatures
Answer:
1. from 2. to
Explanation:
does changing the size of a substance affect its density
Answer:
yes
Explanation:
the term “ The Universe “refers to ?
Answer:
everything including the space...
hope it helps...
Which rule or principle does this violate?
A. Aufbau Principle
B. Pauli Exclusion Principle
C. Hunds rule
Answer:
Hunds rule is violated here.
Hunds rule : pairing of electrons takes place only if all the orbitals are filled with single electrons each.
All matter has a distinct melting and boiling point that we can use to describe it. Look at these thermometers. They show the temperatures at which each type of matter change from solid to liquid to gas. Use these thermometers to answer the questions on this worksheet.Preview the document
Answer:
Química orgánica
Explanation:
Which property is a chemical property of a substance?
color
melting point
reactivity
boiling point
Answer:
Reactivity! :)
Explanation:
I just took the test! "2.13 Physical and Chemical Changes"
Reactivity is the chemical property of the substance. Therefore, option (C) is correct.
What are the chemical properties?A chemical property can be described as the property that causes a change in the chemical structure of the substance. A chemical property of a substance can be seen in chemical change or reaction in the substance.
A chemical property represents the ability of a substance to combine with other substances or convert into a different product. The chemical composition is the identity of the substance and on changing it the substance turns into a different substance.
A chemical property gets determined when a change occurs in the chemical identity of the substance. The chemical properties such as toxicity, reactivity, enthalpy of formation, the heat of combustion, oxidation states, radioactivity, etc.
The color, melting point, and boiling point are the physical properties of a substance while reactivity is the chemical property.
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Why is it beneficial for chemists to understand as many periodic trends as they can?
Answer:
It can help identify elements quicker.
Explanation:
Which of the following is not a genetic trait?
Dimples
Hair length
Height
Hair Color
Answer:
I honestly think is hair length
Help me please !!!
Which of the following can be inferred from the diagram above that shows the dependence of potential Energy on the Internuclear distance between two atoms?
A)The atoms form a bond with a bond length of 25 pm
B)The atoms form a bond with a bond length of 75 pm
с)The net force between the atoms is attractive at 25 pm
D)The net force between the atoms is attractive at 75 pm
Answer:
Its B. The atoms form a bond with a bond lenth of 75 pm
hii if you could help that would be great, if the answer is correct ill mark as brainliest :)))
Answer:
Reactants, Products is the answer i believe
Answer:
reactants, products
Explanation:
A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.
33) How many significant figures does the number 40230 have? *
Answer:
5
Explanation:
they are all significant All non-zero numbers ARE significant
The molecular mass of CO2 is 44.01 u. What is the mass of 2.0 mol of CO2?
Answer:
The mass of 2.0 mol of C02 is 44 grams
Explanation:
The weight of CO2 is 44 grams per mole (1 x 12 grams/mole for the carbon and 2 x 16 grams/mole for the oxygen atoms)
According to the mole concept, the mass of 2.0 mole of carbon dioxide is 88.02 u.
What is a mole?Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons.Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.
Mass can be calculated by the number of moles formula as,
mass=number of moles×molar mass
=2×44.01=88.02 u.
Thus, the mass of 2.0 mole of carbon dioxide is 88.02 u.
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Help with science pleaseee
Answer:
thermal energy
Explanation:
the sun used thermal energy to melt the icecream
We are encouraged to follow the 3 W's --
--Wait 6 feet apart
--Wear a mask over your nose and mouth
--Wash your hands throughly.
Which of these 3 W's would you consider to be a rule you follow in every science lab?
In your answer:
1. State the W
2. Explain why you think this is important for Science Safety.
Answer: Wash your hand Througly
Explanation:The things you handle in a lab can be dangerous and seeing as though it is a common habit to touch your skin and your face the things handled can make you and others sick. Washing your hands after every science lab session is essential to lab and outside lab safety.
PLEASE HELP ASAP!!!
K+ has how many electrons?
-19
-18
-20
-none of these
Answer:
Its 19.
Explanation:
K (potassium) has 19 electron according to the atomic number in the periodic table. The atomic number tells you the number of protons and electrons.
Can someone help me asap... my science teacher assigned this puzzle for us for our 'Atoms Escape Room'
My teacher told me that I have to decode the message using the decoder on the first picture I have attached below.
I still don't get it .....
Please help me asap. thank you.
Answer:
neutrons in c,o,b,h
Explanation:
i think so
Answer:
6860
Explanation:
The oxidation number of oxygen is -2, and that of chlorine is -1. Use this information to match the names of the compounds to their chemical formulas. manganese(II) chloride manganese(IV) chloride manganese(II) oxide manganese(IV) oxide MnCl2 arrowRight MnO2 arrowRight
Answer : The correct formula of manganese(II) chloride and manganese(II) oxide is [tex]MnCl_2[/tex] and [tex]MnO[/tex] respectively.
Explanation :
As we know that the chemical formula is formed by the criss-cross method.
In criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions.
For formation of manganese(II) chloride, manganese will form having an oxidation state of +2 called as cation and anion is chloride with oxidation state of -1.Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .
For formation of manganese(II) oxide, manganese will form having an oxidation state of +2 called as cation and anion is oxide with oxidation state of -2.Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral .
Hence, the correct formula of manganese(II) chloride and manganese(II) oxide is [tex]MnCl_2[/tex] and [tex]MnO[/tex] respectively.
The oxidation number of oxygen is -2, and that of chlorine is -1
The top guy is wrong↑
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Help
I don't understand
I think that is A and D ?
Question 1
Put these elements in order of the INCREASING the atomic radius.
Li, O, C, F
A)O, C, F, Li
B) Li, C, OF
C) F, O, C, Li
D) C, F, Li, o
Explanation:
we know that,
From Left to right (Period) atomic radius decreases
and
From Top to bottom (Group) atomic radius increases.
Li, C, O, F belongs to same period.
So,
Atomic radius decreases if we go left to right
Increasing order of Atomic radius -
Li > C > O > F
Therefore,
Option C is correct ✔.
Answer: C
Explanation:
in the modern periodic table elements are raised according to increasing
Answer:
in the modern periodic table elements are raised according to increasing atomic number
The atomic number equals:
O The number of protons and the number of neutrons.
O The number of protons and the number of electrons.
The number of electrons and the number of neutrons.
O The number of protons plus the number of neutrons.
Answer:
B- the number of protons and the number of electrons.
Explanation:
The atomic number equals the change on the nucleus. It therefore also equals the number of protons in the nucleus and also equals numerically the number of electrons in thw neutral atom. The atomic number has the symbol Z.
PLEASE HELP ASAP!!!
What is the mass of the element above?
-1
-2
-3
-4
-5
Answer:
its 1 not negative
the atom shown below was hydrogen, known as H.
In order to survive, plants absorb sunlight, water, and nutrients from the soil. What property is this?
Plants are unique organisms that can absorb nutrients and water through their root system, as well as carbon dioxide from the atmosphere. Soil quality and climate are the major determinants of plant distribution and growth.
A student is examining an object in science class. It is pale yellow,brittle solid, with no shine. The sample is most likely a—
Answer: non metal
Explanation:
Nonmetals are dull, possess high ionization energies and electronegatives and are typically poor electricity conductors as they're insulators.
Non metals are also brittle and possess low melting point. Therefore, with the explanation, the sample is most likely a non metal.
Which of the following can cause the substance to change phase? Select all that apply.
change in temperature
change of shape
change in mass
change in pressure
Answer:
a and d
Explanation:
HELP ASAP
The diagram below shows some subatomic particles.
What is the particle that is labeled with a question mark (?) in the diagram?
Answer:
The Answer Is Quarks
Explanation:
Its mad up of Quarks
i hope this helps
pls make me brilliant or something
The particle that is labeled with a question mark (?) in the diagram is Quarks
Quarks are elementary particles and fundamental constituents of matter. They are considered the smallest known particles that make up protons and neutrons, which are the building blocks of atomic nuclei. Quarks are classified as fermions, which means they follow the rules of quantum mechanics and obey the Pauli exclusion principle.
There are six known types, or flavors, of quarks: up (u), down (d), charm (c), strange (s), top (t), and bottom (b). Each quark flavor has a unique set of properties, including mass, electric charge, and the way they interact with other particles through the strong nuclear force. The up and down quarks are the lightest and most common, while the top quark is the heaviest.
One notable property of quarks is that they possess a fractional electric charge. The up quark has a charge of +2/3 (e/3), while the down quark has a charge of -1/3 (-e/3), where "e" represents the elementary charge carried by an electron. Quarks are never found in isolation due to the confinement principle, which means they are always bound together in composite particles called hadrons.
Quarks interact through the strong nuclear force, which is mediated by particles called gluons. This force binds quarks together to form protons and neutrons, and also governs the interactions within atomic nuclei.
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