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
8090 [49]
3 years ago
8

If a sample of DNA contained 20% cytosine, what percentage of guaninewould be in this sample and what percentage of adenine woul

d be in the sample
Chemistry
1 answer:
timofeeve [1]3 years ago
7 0
Guanine and Cytosine are complementary pairs in the DNA molecule (which means that Cytosine is bonded via hydrogen bonds to Guanine).  This is the same for Adenine and Thymine.  As such if a sample of DNA contains 20% Cytosine then it also contains approximately 20% Guanine.

The percentage of Thymine + Adenine would be 100% - 40% = 60%... Since this 60% should be equally shared between Thymine and Adenine then it implies that the percentage Adenine would be approximately 30%.
You might be interested in
Elimination of the pharmaceutical IV antibiotic gentamicin follows first-order kinetics. If the half-life of gentamicin is 1.5 h
Genrish500 [490]

Explanation:

The given data is:

The half-life of gentamicin is 1.5 hrs.

The reaction follows first-order kinetics.

The initial concentration of the reactants is 8.4 x 10-5 M.

The concentration of reactant after 8 hrs can be calculated as shown below:

The formula of the half-life of the first-order reaction is:

k=\frac{0.693}{t_1_/_2}

Where k = rate constant

t1/2=half-life

So, the rate constant k value is:

k=\frac{0.693}{1.5 hrs}

The expression for the rate constant is :

k=\frac{2.303}{t} log \frac{initial concentration}{concentration after time "t"}

Substitute the given values and the k value in this formula to get the concentration of the reactant after time 8 hrs is shown below:

\frac{0.693}{1.5 hrs} =\frac{2.303}{8 hrs} x log \frac{8.4x10^-^5}{y} \\ log \frac{8.4x10^-^5}{y} =1.604\\\frac{8.4x10^-^5}{y}=10^1^.^6^0^4\\\frac{8.4x10^-^5}{y}=40.18\\y=\frac{8.4x10^-^5}{40.18} \\=>y=2.09x10^-^6

Answer: The concentration of reactant remains after 8 hours is 2.09x10^-6M.

5 0
3 years ago
I want to know the steps.
Artyom0805 [142]

The answer for the following problem is described below.

<em><u> Therefore the standard enthalpy of combustion is -2800 kJ</u></em>

Explanation:

Given:

enthalpy of combustion of glucose(ΔH_{f} of C_{6}H_{12} O_{6}) =-1275.0

enthalpy of combustion of oxygen(ΔH_{f} of O_{2}) = zero

enthalpy of combustion of carbon dioxide(ΔH_{f} of CO_{2}) = -393.5

enthalpy of combustion of water(ΔH_{f} of H_{2} O) = -285.8

To solve :

standard enthalpy of combustion

We know;

ΔH_{f}  = ∈ΔH_{f} (products) - ∈ΔH_{f} (reactants)

C_{6}H_{12} O_{6} (s) +6 O_{2}(g) → 6 CO_{2} (g)+ 6 H_{2} O(l)

ΔH_{f} = [6 (-393.5) + 6(-285.8)] - [6 (0) + (-1275)]

ΔH_{f} = [6 (-393.5) + 6(-285.8)] - [0 - 1275]

ΔH_{f} = 6 (-393.5) + 6(-285.8)  - 0 + 1275

ΔH_{f} = -2361 - 1714 - 0 + 1275

ΔH_{f} =-2800 kJ

<em><u> Therefore the standard enthalpy of combustion is -2800 kJ</u></em>

7 0
3 years ago
If the formula for a compound is represented by X3Y2 and the charge on the Y ion is -3, what is the charge in the X ion?
artcher [175]
I cannot fully remember but the charge of a compound always has to be the same.  However, I believe that the sign of the Y2 means that it is positive 2. 

so in my opinion it is in between b and c. use your best judgment. 
3 0
3 years ago
Fill in the coefficients that will balance the following reaction:
Alex17521 [72]

Answer:

To balance a reaction, the amount of reactants must be equal to the amount of products, as stated by the Law of Conservation of Matter. It may help you to keep track of  the number of each element in a list as you try to balance. It's not able to be balanced.

3 0
3 years ago
Read 2 more answers
After wood burns, the ash weighs much less than the original wood. explain why the law of conservation of mass is not violated i
Annette [7]
When wood burns it makes 1 ash and 2 CO and so law of conversation matter wouldn't be violated as the ash + the smoke each would have a fraction of the original matter from the wood
8 0
3 years ago
Read 2 more answers
Other questions:
  • 2 Points
    8·2 answers
  • When two atoms combine by transferring electrons, it is a(n) _____ bond.<br> ionic<br> covalent
    15·1 answer
  • I WILL GIVE BRAINLIEST!
    15·2 answers
  • Is be2+ stable or not?<br> is Ne stable or not?<br> is Br- stable or not?<br> is h+ stable or not?
    12·2 answers
  • Given 25.43 g of O2 gas, how many liters of gas will you have at STP?<br><br>Answer value
    7·1 answer
  • How many liters of fat would have to be removed to result in a 5.2 lb weight loss? The density of human fat is 0.94 g/mL?​
    15·1 answer
  • Which phrase best describes earths atmosphere
    7·1 answer
  • Which of these is the most powerful force of weathering and erosion?
    7·2 answers
  • PLEASE HELP! I'LL GIVE YOU BRAINLIEST!
    9·2 answers
  • if 1.386 g of mg ribbon combusts to form 2.309 g of oxide product, calculate the experimental mass percent of oxygen from this d
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!