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.
How 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
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.
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
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.
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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Boyle's Law Problems
Charles' Law Problems
Answer:
here are the answers babe. Feel free to ask for more
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/molKhelp 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 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!
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.
