First, let's write the givens in the form of a chemical equation:
3A + B ...................> 4X + 2Y
Now we find that this equation implies the following:
For every 4X and 2Y formation, 3A and 1B must disappear (react).
Comparing this implication to the above choices, we find that the right answer is: <span>The rate of formation of X is four times the rate of disappearance of B.</span>
The half life of uranium- 238 is
4.46 x10^9 years
Explanation
Half life is the time taken for the radioactivity of a isotope to fall to half its original value.
The original mass of uranium-238 is 4.0 mg
Half of original mass of uranium = 4.0 mg /2 = 2.0 mg
since it take 4.46 x 10^ 9 years for the sample to half the half life of uranium -238 = 4.46 x10^9 years
Rate law for the given 2nd order reaction is:
Rate = k[a]2
Given data:
rate constant k = 0.150 m-1s-1
initial concentration, [a] = 0.250 M
reaction time, t = 5.00 min = 5.00 min * 60 s/s = 300 s
To determine:
Concentration at time t = 300 s i.e. ![[a]_{t}](https://tex.z-dn.net/?f=%5Ba%5D_%7Bt%7D)
Calculations:
The second order rate equation is:
![1/[a]_{t} = kt +1/[a]](https://tex.z-dn.net/?f=1%2F%5Ba%5D_%7Bt%7D%20%3D%20kt%20%2B1%2F%5Ba%5D)
substituting for k,t and [a] we get:
1/[a]t = 0.150 M-1s-1 * 300 s + 1/[0.250]M
1/[a]t = 49 M-1
[a]t = 1/49 M-1 = 0.0204 M
Hence the concentration of 'a' after t = 5min is 0.020 M
Answer:
C. involve the attraction of opposite charges
Explanation:
<em>Ionic bonding</em> involves the attraction between <em>oppositely charged ions</em>, as in Na⁺ Cl⁻.
<em>Covalent bonding</em> involves the attraction between <em>negatively charged electrons and positivey charged nuclei</em>, as in a C-H bond.
A is <em>wrong</em>. Ionic bonding involves the transfer of electrons.
B is <em>wrong</em>. Covalent bonding involves the sharing of electrons.
D is <em>wrong</em>. Ionic bonds are usually stronger than covalent bonds.
Answer:
endoplasmic reticulum:
✔ helps in the production and movement of materials
Golgi body:
✔ packages and distributes materials in and out of cell
mitochondrion:
✔ supplies energy that the cell uses
ribosome:
✔ produces proteins for the cell
Explanation:
took test :D
