Answer:
It will take 6.6 hours for 75% of the lead to decay.
Explanation:
The radioactive decay follows first order rate law
The half life and rate constant are related as
The rate law for first order reaction is
Where
A0 = initial concentration = 1 g
At= final concentration = 0.25 g (as 75% undergoes decay so 25% left]
Answer: Yes, it is possible for each samples to contain 1 mole of a substance because the number of moles are not dependent on the mass or the volume.
Explanation:
The formula for the number of moles is given by:
As, the masses of 2 samples are different, so the number of moles will be dependent only on the molar masses of the samples.
Volume has no effect on the number of moles.
Answer:
use the rule of speed
Explanation:
speed =distance over time
Answer:
Filling in the blank, this is an example of <u>chemical weathering</u> which happens <u>to rocks</u> overtime.
Explanation:
Chemical weathering occurs when rocks are disintegrated by chemicals.
Rain water becomes acid rain when it reacts with carbon dioxide in the atmosphere (to form carbonic acid, HCO3).
When acidic rainwater falls and stays on rocks, chemical reactions take place with the minerals present in the rock, causing the rock to weather.
Areas with immense carbon dioxide and sulphur dioxide pollution increases rain water acidity, which in turn causes moisture in the atmosphere to dissolve these gases and produce acid rain.
<u>Answer:</u> The pressure that must be applied to the apparatus is 0.239 atm
<u>Explanation:</u>
To calculate the osmotic pressure, we use the equation for osmotic pressure, which is:
or,
where,
= osmotic pressure of the solution
i = Van't hoff factor = 1 (for non-electrolytes)
= mass of sucrose = 3.40 g
= molar mass of sucrose = 342.3 g/mol
= Volume of solution = 1 L
R = Gas constant =
T = temperature of the solution =
Putting values in above equation, we get:
Hence, the pressure that must be applied to the apparatus is 0.239 atm