Answer:
[tex]0.564[/tex]
Explanation:
Hello,
In this case, by performing the given division we obtain:
[tex]\frac{9.15}{16.23}=0.563770795[/tex]
Nevertheless since 9.15 has three significant figures and 16.23 four, we must show the result with three significant figures taking into account that it must be shown with the least significant figures from the initial data:
[tex]0.564[/tex]
Regards.
What are the advantages of having proof before you make any conclusion about your own understanding for scientific method?
Answer:
Helps in accepting and defending the conclusion.
Explanation:
The main advantages of having proof before you make any conclusion is that it gives a reason for accepting the answer given by you because you have the proof to prove your answer so no one questions on your answer. The proof give you strength to defend your conclusion and make your conclusion right in front of the world. Without proof no one can accept your answer because every answer of a scientific question wants a proof for its validation.
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What type of change, physical or chemical, takes place in each
of the following?
a. Pie dough is rolled into thin pieces for a crust.
b. A silver pin tarnishes in the air.
c. A tree is cut into boards at a saw mill.
d. Food is digested.
e. A chocolate bar melts.
Answer:
a. Physical Change
b. Chemical Change
c. Physical Change
d. Chemical Change
e. Physical Change
Physical and chemical change has been differentiated by the formation of new substances. Silver pin tarnishing and digestion of food are considered chemical changes. Thus, options b and d are correct.
What are physical and chemical changes?Chemical changes are characterized by alterations in the properties of the substances that results in the formation of new substances that differs in their composition and properties. These changes are said to be permanent changes that cannot be reversed back into their main constituents.
Physical changes are said to be temporary changes that are reversible as the substance produced has the same structures and includes changes in texture, color, pattern, temperature, state of matter, etc.
Silver tarnishes under air is a chemical change as it undergoes a chemical reaction under oxygen and produces a new product. Digestion of food is also a chemical change that breaks the food into smaller pieces under the action of the enzymes.
Rolling of the pie dough, cutting the trees into boards, and melting the chocolate bars are physical changes as no new substances with different chemical compositions are produced.
Learn more about physical and chemical change, here:
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Look up the molecular weight of Lithium diisoproylamine and determine the amount of g of base needed for this experiment. Round to the hundredths place
Answer:
0.72 g
Explanation:
Note that, the mass in gram of any substance is obtained from the relationship;
Mass= number of moles × molar mass
From the sequence of the reaction, the number of moles of Lithium diisopropylamide is 6.75mmol which is the same as 6.75 × 10^-3 moles
Molar mass of base= 107.1233 g/mol
Hence mass of the base is given by;
6.75 × 10^-3 moles × 107.1233 g/mol = 0.72 g
How many bonding and antibonding molecular orbitals are there in methane, CH4?
Bonding orbitals Antibonding orbitals
Zero Zero
One One
Two Two
Three Three
Four Four
Answer:
Four Four
Explanation:
A molecule is formed by the overlap of orbitals. The combination of atomic orbitals during bond formation leads to the formation of bonding and anti bonding molecular orbitals.
When a molecule is formed, the number of bonding molecular orbitals must be equal to the number of anti bonding molecular orbitals.
Hence, when methane is formed, four bonding and four anti bonding orbitals are formed because methane forms four bonds per molecule.
g What is the half-life for a particular reaction if the rate law is rate = (1291 M⁻¹*min⁻¹)[A]² and the initial concentration of A is 0.250 M?
Answer:
[tex]t_{1/2}=3.10x10^{-3}min=0.186s[/tex]
Explanation:
Hello,
In this case, for the calculation of the half-life for the mentioned reaction we first must realize that considering the units of the rate constant and the form of the rate law, it is a second-order reaction, therefore, the half-life expression is:
[tex]t_{1/2}=\frac{1}{k[A]_0}[/tex]
Therefore, we obtain:
[tex]t_{1/2}=\frac{1}{1291\frac{1}{M*min}*0.250M}\\\\t_{1/2}=3.10x10^{-3}min=0.186s[/tex]
Regards.
The half-life for the reaction is 0.003 mins
From the question given above, the following data were obtained:
Rate law = (1291 M⁻¹min⁻¹)[A]²
Initial concentration of A = 0.250 M
Half-life (t½) =?From the rate law given, we can see that the reaction is indicating a 2nd order reaction.
Thus, the half-life can be obtained as follow:
t½ = 1 / K[A₀]
t½ = 1 / (1291 × 0.25)
t½ = 0.003 minsTherefore, the half-life for the reaction is 0.003 mins
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