name the gas which is formed when coal is heated in the absense of air
Answer:
Coke
Explanation:
A solid fuel formed by heating coal in the absence of air is coke. Coke is black colored, tough porous substance. It is pure carbon.
An oxygen atom has 8 protons. What number of neutrons would make an
oxygen atom most stable?
A. 10
B. 6
C. 12
D. 8
D. 8
Hope this helps! :)
______________
Answer:
D: 8 neutrons would make it most stable
What type of nuclear decay is shown by the reaction below?
A. Alpha
B. Gamma
C. Beta
O D. Fission
Answer:
C. Beta
Explanation:
What point A on the phase diagram called?
liquid
(374°C/218 atm)
A
solid
pressure (atm)
gas
temperature (°C)
OA.
the melting point
OB.
the boiling point
Ос.
the freezing point
OD
the critical point
OE.
the triple point
Answer:
D) the critical point
Explanation:
Point A is the critical point in phase diagram. This is the highest temperature and pressure at which a pure material can exist in vapor/liquid equilibrium. Pretty cool!
What does a low number on the pH scale say about a solution?
A. The solution is neutral.
B. The solution is a base.
C. The solution is changing.
D. The solution is an acid.
Answer:
d. the solution is a acid
Answer:D The solution is an acid
Explanation:The lower the pH of a substance the stronger the acidic level.
How many electron containing orbitals are in an atom of tin ?
Answer:
10
Explanation:
how many electron-containing d orbitals are there in an atom of tin? name the element in the 4th period whose atoms have the same number of highest-energy-level elctrons as tin
10, germanium
Two or more than two atoms with different physical or chemical properties can not combine together to form an element. Therefore, the total number of orbitals containing electrons in an atom of tin are 10 orbitals.
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
The electronic configuration of tin is 1s² 2s² 2p⁶ 3s²3p⁶ 4s² 3d¹⁰ 4p⁶ 5s²4d¹⁰ 5p² or [Kr] 5s² 4d¹⁰ 5p². The total number of orbitals containing electrons in an atom of tin are 10 orbitals. tin an element that belongs to p block of periodic table.
Therefore, the total number of orbitals containing electrons in an atom of tin are 10 orbitals.
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HELP! HELP! Calculate the value of ΔS⁰ at 298 K.
Answer:
ΔS⁰ = -181.1J/molK
Explanation:
ΔS⁰ of a reaction is defined as the sum of the entropies of the reactants times its reaction coefficient minus the sum of the entropies of the products times its reaction coefficient. For the reaction in the problem:
ΔS⁰ = 2*S{NaCl(s)} - (2*S{Na(s)}+S{Cl2(g)})
ΔS⁰ = 2*72.1J/molK - (2*51.1J/molK + 223.1J/molK)
ΔS⁰ = -181.1J/molKHow many atoms are in 490 moles of barium?
Answer:
2.95 * 10^23 atoms
Explanation:
The number of atoms in a mole is always equal to Avogadro's constant, which is 6.02214076×10²³ mol⁻¹.
To find the number of atoms in 0.490 moles of barium, multiply it with Avogadro's constant:
0.490 mol * 6.02214076×10²³ mol⁻¹ ≈ 2.9508 * 10^23
Convert to SigFigs (if necessary):
2.95 * 10^23
CHEMISTRY HW... DUE in 2.5 hours! HELP!!!!
Answer:
The final temperature aluminium-water system is 24° C
Explanation:
Heat energy, H = mcθ
Where m is mass of substance, c is specific heat capacity, θ is temperature difference
Using the principle, Heat lost = Heat gained
Let the final temperature of the aluminium-water system be Tfinal
Heat lost by aluminium, H₁ = -m₁c₁(Tfinal - 40)
Heat gained by water, H₂ = m₂c₂(Tfinal -21)
Heat lost by aluminium, H = -[30 × 0.21 × (Tfinal - 40)]
H₁ = -6.3Tfinal + 252
Heat gained by water, H₂ = 50 × 1.0 × (Tfinal - 21)
H₂ = 5Tfinal - 21
Equating H₁ and H₂
-6.3Tfinal + 252 = 5 Tfinal - 21
5Tfinal + 6.3Ffinal = 252 + 21
11.3 Tfinal = 273
Tfinal = 273/11.3
Tfinal = 24° C
Therefore, the final temperature aluminium-water system is 24° C
Which of the following is not a reason why actual yield is less than theoretical yield?
A. presence of impure reactants
B. conservation of mass
C. competing side reactions
D. loss of product during purification
The option that isn't a reason why the actual yield is less than theoretical yield is B. conservation of mass.
It should be noted that the formula for the percent yield is given as:
= Actual yield / Theoretical Yield × 100
The actual yield is experimentally determined, and it's the quantity of a product that is gotten from a chemical reaction.The theoretical yield is the amount of product that can be obtained from a reaction when the reactants are changed to products.Actual yield can be less than theoretical yield due to the presence of impure reactants ,competing side reactions, and loss of product during purification.
In conclusion, the correct option is B.
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Increasing the concentration increases the speed of reaction by... increasing the number of collisions between products increasing the amount of energy in the system increasing the number of collisions between reactants lowering the activation energy of the reaction
Answer: increasing the number of collisions between reactants
Explanation:
A reaction is possible due to collisions between the reactants to create products. If we increase the concentration of reactants then that means that we are increasing the molecules of the reactants which would give them more chances to collide and make products.
For instance, using a non-chemistry example, if there are few cars in a large city, the accidents there will be less because the cars will have such space that they wouldn't collide with each other. If the number of cars in the city is increased however, there is now less space and more chances for cars to collide.
What is a reaction rate
Answer:
Explanation:
A reaction rate is the measure of the change in concentration of the disappearance of reactants or the change in concentration of the appearance of products per unit time
Boyle's Law Problems
Charles' Law Problems
Answer:
here are the answers babe. Feel free to ask for more
Why do we need to know these organic molecules?
Are they important to living things?
Answer:
Organic molecules are important to living things because life is based on the properties of carbon.
Properties of Carbon
Carbon is an important element because it can form four covalent bonds.
Carbon skeletons can vary in length, branching, and ring structure.
The carbon skeletons contain the functional groups that are involved in biochemical
Explanation:
Hope it helps
Is the number of electrons in different shells of an atom fixed or unlimited ? Explain by giving an example.
Answer:
the number of electrons in a particular shell is given by the formula 2n^2 . However an electron when gets very exicited loose energy in the forms of radiation and comes in high energy level shell.
rare earth elements plz
Answer:
Rare earth elements are lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium - that appear in low concentrations in the ground.
Explanation:
The rare earth elements (REE) are a set of seventeen metallic elements. These include the fifteen lanthanides on the periodic table plus scandium and yttrium. Rare earth elements are an essential part of many high-tech devices.
How does an indicator show the difference between an acid and an alkali?
Explanation:
When a base dissolves in water it is an alkali and makes an alkaline solution.
...
Litmus.
Red Litmus Blue Litmus
Acidic solution Stays red Turns red
Neutral solution Stays red Stays blue
Alkaline solution Turns blue Stays blue
Help please I’ll give you brainless
Answer:
Step 9
Explanation:
The reason i selected step 9, is if you take a look at the picture hes setting up a funnel,With filter paper and if you take a look at number ''9'' questions it says set up a funnel, filter paper and filter flask which is shown in the picture on top that's how i got my answer
Which two of the following changes of state involve solids?
Select two (2) answers
A. melting
B. boiling
C. freezing
D. evaporating
Answer:
Answer is A... Melting and freezing
Jason combines the two intermediate steps shown. 2 equations. First: upper N subscript 2 (g) plus upper O subscript 2 (g) right arrow 2 upper N upper O (g). Second: 2 upper N upper O (g) plus upper O subscript 2 (g) right arrow 2 upper N upper O subscript 2 (g). Which best describes what Jason should do with the oxygen molecules?
Answer:
The molecules of oxygen should be placed as reactants in the equation.
Explanation:
1: N₂ + O₂ → 2NO
2: 2NO + O₂ → 2NO₂
complete reaction:
N₂ + 2O₂ → 2NO₂
In both intermediate equations' oxygen is used as reactant because the end product is the product of the combination of nitrogen and oxygen. So in the complete or overall reaction, oxygen should also be placed as reactant.We can not place oxygen at the side of products neither we can cancel it because, products can only be obtained at the end of the reaction but according to the equations' oxygen is not the end product of the reaction. But the addition into the reaction (Eq. 2) to make the new product.
Also, we can not cancel it because to cancel out molecules of oxygen should be present at the both sides with same amount in the stoichiometric equation.
Hence, in a balanced chemical equation, oxygen should be written as a reactant by using the correct number of moles.
How much energy does a 930 nm wave of light have? (The speed of light in a vacuum is 3.00 x 108 m/s, and Planck's constant is 6.626 x 10-34 J·s.)
A. 4.68 x 10^18 J
B. 2.14 x 10^-19 J
C. 1.85 x 10^-31 J
D. 4.21 x 10^35 J
Answer:
B. 2.14 x 10^-19 J
Explanation:
The energy of a wave of light can be obtained using the equation:
E = h*c/λ
Where E is the energy in joules,
λ is wavelength = 930nm = 930x10⁻⁹m
h = Planck's constant = 6.626x10⁻³⁴Js
c = Speed of light = 3.00x10⁸m/s
Replacing:
E = 6.626x10⁻³⁴Js*3.00x10⁸m/s/930x10⁻⁹m
E = 2.14x10⁻¹⁹J
Right option is:
B. 2.14 x 10^-19 J
help me with this attachment please
Answer:
See explanation
Explanation:
Let us recall that the basic rule in writing balanced chemical reaction equations is that the number of atoms of each element on the right hand side of the reaction equation is the same of the number of atoms of the same element on the left hand side of the reaction equation.
The reaction of red hot iron and steam is written as follows;
3Fe + 4H2O → Fe3O4 + 4H2.
The decomposition reaction of ammonium dichromate is written as;
(NH4)2Cr2O7 → N2 + Cr2O3 + 4H2O
Reaction of aluminium, sodium hydroxide and water is as follows,
2Al + 2NaOH + 2H2O ----> 2NaAlO2 + 3H2
Reaction of potassium bicarbonate with sulphuric acid;
2KHCO3 + H2SO4 -------> K2SO4 + 2H2O + 2CO2
Reaction of zinc and sodium hydroxide is as follows;
Zn + 2NaOH→Na2ZnO2 + H2
What properties can be used to identify substance and why?
Answer:
All substances can be characterized by their unique sets of physical and chemical properties. Properties that can be determined without changing the composition of a substance are referred to as physical properties. Characteristics such as melting point, boiling point, density, solubility, color, odor, etc.
State the name(s) of the sub-atomic particle(s) that have/has a positive charge. Answer with the name of the particle(s) only.
A. Neurons
B. Protons
C. Electrons
Answer:
protons because they have the most positive charge
