Answer:
a. .250 moles
Explanation:
Hello!
In this case, since we can see how the hydrogen is given off as a product of the reaction and we can model its behavior via the ideal gas equation, it is possible for us to use such equation for the determination of the collected moles:
Next, since the STP conditions account for a pressure of 1 atm and a temperature of 273 K, the moles turn out to be:
Thus the answer is a. .250 moles
.
Best regards!
Answer: e) all of these
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water , carbon dioxide
Mixtures are not pure substances as they consist of elements and compounds combined physically and not in any fixed ratio. Example: Air
Thus all given substances are pure substances.
Answer:
0.000121 year⁻¹
Explanation:
The half life is defined as the time at which the reactant's concentration reduced to half.
The formula for the half life for a first order kinetic reaction is:
Where,
is the half life
k is the rate constant.
Thus, Given that:
Half life = 5730 years
Where, k is rate constant
So,
<u>The rate constant or decay constant, k = 0.000121 year⁻¹</u>
D= mass over volume
So, density equals 9.0g divided by 45ml.
SO, D=.25 g/ml
I'm not 100% sure this is correct, though. Best if luck. ♡