Please help extra points

The half-life of the radioactive element unobtanium-43 is 10 seconds. If 48 grams of unobtanium-43 are initially present, how ma

natka813 [3]

Answer:

At time, 10 seconds, the mass remaining is 24 grams

At time, 20 seconds, the mass remaining is 12 grams

At time, 30 seconds, the mass remaining is 6 grams

At time, 40 seconds, the mass remaining is 3 grams

At time, 50 seconds, the mass remaining is 1.5 grams

Step-by-step explanation:

Given;

initial mass of the radioactive element = 48 grams

half life, t = 10 seconds

time of decay (s) remaining mass of the radioactive element

0 ------------------------------------------------- 48 grams

10------------------------------------------------- 24 grams

20 ------------------------------------------------- 12 grams

30 -------------------------------------------------- 6 grams

40 --------------------------------------------------- 3 grams

50 ----------------------------------------------------- 1.5 grams

60------------------------------------------------------0.75 grams

Thus;

At time, 10 seconds, the mass remaining is 24 grams

At time, 20 seconds, the mass remaining is 12 grams

At time, 30 seconds, the mass remaining is 6 grams

At time, 40 seconds, the mass remaining is 3 grams

At time, 50 seconds, the mass remaining is 1.5 grams

7 0

3 years ago

A scientist needs 4.8 liters of a 12% alcohol solution. She has available a 22% and a 10% solution. How many liters of the 22% a

yanalaym [24]

Answer:

4.0 L of 10%
0.8 L of 22%

Step-by-step explanation:

For mixture problems, it is convenient to define a variable to represent the amount of the greatest contributor. Let x represent the amount of 22% solution in the mix. Then 4.8-x is the amount of 10% solution.

The amount of alcohol in the mix is ...

0.22x +0.10(4.8-x) = 0.12(4.8)

Eliminating parentheses, we have ...

0.22x -0.10x +0.10(4.8) = 0.12(4.8)

Subtracting (0.10)(4.8) and combining x-terms gives ...

0.12x = 0.02(4.8)

x = (0.02/0.12)(4.8) = 0.8 . . . . . divide by the x-coefficient

The scientist needs 0.8 L of 22% solution and 4.0 L of 10% solution.

5 0

3 years ago

Find the infinite sum of 10,5,2.5,1.25...

____ [38]

Notice this is a geometric progression since each number multiplied by some factor equals the next number in the sequence, in this case,

$10 \times r = 5 \Rightarrow r=0.5$

Then by applying the formula for sum to infinity of a geometric progression,
$S_\infty = \frac{a}{1-r} = \frac{10}{1-0.5} = 20$

3 0

3 years ago

Read 2 more answers

IF I HAVE A LAPTOP COMPUTER THAT MEASURES 30.8×6.6×39.8 CENTIMETERS...WHAT SIZE CASE DOES IT REQUIRE

soldi70 [24.7K]

Answer:

8090.54

Step-by-step explanation:

30.8*6.6*39.8

4 0

3 years ago

What is the velocity of a bird with a mass of 2 kilograms flying at 60 kg*m/s?

scoundrel [369]

Answer:

30 m/s

Step-by-step explanation:

p = mv

momentum = mass × velocity

here the momentum is 60kgm/s

mass is 2kg

substitute in the equation

60 = 2v

v= 30m/s

4 0

4 years ago