The mass number is the number of protons plus the number of neutrons. Since there are 16 neutrons, there are 14 protons. This also corresponds to the atomic number, so this atom's atomic number is 14 which is also Silicon
Answer:
Amount left after 25 days = 12.5 g
Explanation:
Given data:
Mass of sample = 400 g
Half life of sample = 5 days
Mass left after 25 days = ?
Solution:
First of all we will calculate the number of half lives passes in given time period.
Number of half lives = Time elapsed / Half life
Number of half lives = 25 days/ 5 days
Number of half lives = 5
At time zero = 400 g
At 1st half life = 400 g/2 = 200 g
At 2nd half life = 200 g/2 = 100 g
At 3rd half life = 100 g/2 = 50 g
At 4th half life = 50 g/2 = 25 g
At 5th half life = 25 g/2 = 12.5 g
Answer:
C. 4.00 K
Explanation:
We can solve this using Charles's Law of the ideal gas. The law describes that when the pressure is constant, the volume will be directly proportional to the temperature. Note that the temperature here should only use the Kelvin unit. Before compressed, the volume of the gas is 50ml(V1) and the temperature is 20K (T1). After compressed the volume becomes 10ml(V2). The calculation will be:
V1 / T1= V2 / T2
50ml / 20K = 10ml / T2
T2= 10ml/ 50ml * 20K
T2= 4K
<u>Answer:</u> The osmotic pressure is 54307.94 Torr.
<u>Explanation:</u>
To calculate the concentration of solute, we use the equation for osmotic pressure, which is:
where,
= osmotic pressure of the solution = ?
i = Van't hoff factor = 3
C = concentration of solute = 0.958 M
R = Gas constant = 
T = temperature of the solution = ![30^oC=[30+273]K=303K](https://tex.z-dn.net/?f=30%5EoC%3D%5B30%2B273%5DK%3D303K)
Putting values in above equation, we get:
Hence, the osmotic pressure is 54307.94 Torr.
Answer:
B. Distributed over a very wide range
D. Limited life existence in geologic time.
Explanation:
Index fossils are very unique fossils that helps in determining the relative ages of rocks and biostratigraphic correlation. They are usually called guide fossils.
- Fossils are the preserved remains of dead organisms found in rocks.
- Index fossils are a special class of fossils with the following properties;
- They are widely distributed.
- They have a short stratigraphic range.
- They show rapid evolution trends
