1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
abruzzese [7]
3 years ago
11

PLEASE HELP

Chemistry
2 answers:
anastassius [24]3 years ago
7 0

Answer:

B??? sorry if im wrong

Explanation:

navik [9.2K]3 years ago
4 0
I believe the answer is A.
You might be interested in
How do researchers select a sample that is representative of its population
tiny-mole [99]

Explanation:

Using stratified random sampling, researchers must identify characteristics, divide the population into strata, and proportionally choose individuals for the representative sample. ... For example, individuals who are too busy to participate will be under-represented in the representative sample.

7 0
3 years ago
A sample contains 25% parent isotope and 75% daughter isotopes. If the half-life of the parent isotope is 72 years, how old is t
alisha [4.7K]

The radioactive decay obeys first order kinetics

the rate law expression for radioactive decay is

ln\frac{[A_{0}]}{[A_{t}]}=kt

Where

A0 = initial concentration

At = concentration after time "t"

t = time

k = rate constant

For first order reaction the relation between rate constant and half life is:

k=\frac{0.693}{t_{\frac{1}{2} } }

Let us calculate k

k = 0.693 / 72 = 0.009625 years⁻¹

Given

At = 0.25 A0

ln(\frac{A0}{0.25A0})=0.009625  X time

time = 144 years

So after 144 years the sample contains 25% parent isotope and 75% daughter isotopes**

Simply two half lives

5 0
3 years ago
Read 2 more answers
How much a material takes time to burn?
Nat2105 [25]

(a)- Time

(b)- Heat produced(i guess)

(c)- Material

this is what I think, hope it helps

5 0
3 years ago
Anyone good at chemistry ? Maybe you can help me out?
olga55 [171]
I'm good at chemistry for some advice just message me here or roblox my username is rightchem7 .
4 0
3 years ago
THIS IS A THREE PART QUESTION IF YOU CAN HELP IT WOULD BE REALLY APPRECIATED SO I DONT FAIL.
Nostrana [21]

Answer:

1. B = 1.13M

2. A. 8.46%

3. D = 0.0199

Explanation:

1. Molarity of a a solution = number of moles of solute/ volume of solution in L

Number of moles of solute = mass of solute/molar mass of solute

Molar mass of NaC₂H₃O₂ = 82 g/mol, mass of NaC₂H₃O₂ = 245 g

Number of moles of NaC₂H₃O₂ = 245 g / 82 g/mol = 2.988 moles

Molarity of solution = 2.988 mols/ 2.65 L = 1.13 M

2. Percentage by mass of a substance = mass of substance /mass of solution × 100%

Mass of 2.65 L of water = density × volume

Density of water = 1 Kg/L = 1000 g/L; volume of waterb= 2.65 L

Mass of water = 1000 g/L × 2.65 L = 2650 g

Mass of solution = mass of water + mass of solute = 245 + 2650 =2895 g

Percentage by mass of NaC₂H₃O₂ = 245/2895 × 100% = 8.46%

3. Mole fraction of NaC₂H₃O₂ = moles of NaC₂H₃O₂/moles of solution

Moles of water = mass /molar mass

Mass of water = 2650 g; molar mass of water = 18 g/mol

Moles of water = 2650 g / 18 g/mol = 147.222 moles

Moles of solution = moles of solute + moles of water = 147.222 + 2.988 = 150.21

Moles of NaC₂H₃O₂ =2.988 moles

Moles fraction of NaC₂H₃O₂ =2.988/150.21 = 0.0199

6 0
3 years ago
Other questions:
  • Choose the compound that exhibits hydrogen bonding as its strongest intermolecular force.
    14·2 answers
  • To what category of elements does an element belong if it is a poor conductor of electricity
    13·1 answer
  • Sociologist Lewis Mumford said that language was the most important and significant ___________ humans used.
    5·1 answer
  • "how is the stomach lining protected from the strongly acidic ph of its contents?"
    7·1 answer
  • a 2000ml bottle has a mass of 234g when empty and a mass of 2367g when full of pop. how dense is the pop that is in the bottle
    5·1 answer
  • Write the Rate Law
    15·1 answer
  • If a gas is 0.8L at 900 mm Hg and 400K, what is the new pressure if the volume decreases to 0.5L and 300K?
    10·1 answer
  • How did elements get to earth?
    7·1 answer
  • 2. What is the relationship between mutation, natural selection and adaptation?
    11·1 answer
  • What pressure is required to compress 196.0 liters of air at 1.83 atmosphere into a cylinder whose volume is 26.0 liters
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!