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Nataliya [291]
2 years ago
15

What % of original U238 remains after three half lives? 1-50 2-25 3-12.5 4-6.25

Chemistry
1 answer:
Grace [21]2 years ago
7 0

Answer:

12.5

Explanation:

After three half-lives, one eighth (1/2 x 1/2 x 1/2) of the uranium-238 will remain. One-eighth equals 12.5%

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6. What is the wavelength (in meters) of the electromagnetic carrier wave transmitted by The Sports
Vsevolod [243]

Answer:

wavelength = 2.81 m

Explanation:

Given that,

The frequency of the Sports  Fan radio station, f = 106.4 MHz

We need to find the wavelength (in meters) of the electromagnetic carrier wave. The relation between frequency and wavelength is given by :

c=f\lambda

Where,

\lambda is wavelength

\lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{3\times 10^8}{106.4\times 10^6}\\\\\lambda=2.81\ m

So, the wavelength of the electromagnetic carrier wave is 2.81 m.

8 0
2 years ago
How do you Calculate the molarity of 250 ml of solution in which 2.7 g of MgCl2 are dissolved
IRINA_888 [86]

Answer:

Molar mass of MgCl2 is 95 g/mol

Mg = 24 g/mol and Cl = 35.5 ×2 = 71 g/mol

moles = mass given/ molar mass

= 2.7/95 = 0.028 mol

volume = 250/1000 = 0.25 dm3 (ml is the same as dm3)

molarity of MgCl2 = moles/volume

= 0.028/0.25

= 0.112 mol/dm3

3 0
2 years ago
14. An enzyme-catalyzed reaction was carried out with the substrate concentration initially a thousand times greater than the Km
emmainna [20.7K]

Answer:

27 min

Explanation:

The kinetics of an enzyme-catalyzed reaction can be determined by the equation of Michaelis-Menten:

v = \frac{vmax[S]}{Km + [S]}

Where v is the velocity in the equilibrium, vmax is the maximum velocity of the reaction (which is directed proportionally of the amount of the enzyme), Km is the equilibrium constant and [S] is the concentration of the substrate.

So, initially, the velocity of the formation of the substrate is 12μmol/9min = 1.33 μmol/min

If Km is a thousand times smaller then [S], then

v = vmax[S]/[S]

v = vmax

vmax = 1.33 μmol/min

For the new experiment, with one-third of the enzyme, the maximum velocity must be one third too, so:

vmax = 1.33/3 = 0.443 μmol/min

Km will still be much smaller then [S], so

v = vmax

v = 0.443 μmol/min

For 12 μmol formed:

0.443 = 12/t

t = 12/0.443

t = 27 min

7 0
3 years ago
What is the main greenhouse gas responsible for influencing the world climate
cluponka [151]

Answer:

carbon dioxide

Explanation:

6 0
3 years ago
Properties of iron, barium, and phosphorus. Explain why nails are made of iron but they are never made of barium or phosphorus.
bearhunter [10]

Nails are made up of iron not of phosphorus and barium.  

As both phosphorous and barium are relatively weaker than iron ,phosphorus breaks easily and barium is also fairly weak. Iron nails are already also not that strong, but their weight and strength are sufficient.  

So the nails are made up of iron.

3 0
2 years ago
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