Answer: 17 years
Explanation:
Expression for rate law for first order kinetics for radioactive substance is given by:
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
b) for 8900 g of the mass of the sample to reach 7700 grams
Thus it will take 17 years
The density is the mass of a substance per unit volume. The surface water density is higher at the poles, and lower at the equator. Thus, the statement is false.
<h3>What is the relation between density and latitude?</h3>
The latitude is the distance from the poles. As moving down from the equator, the temperature increases. The increase in temperature at the equator allows larger mass to accumulate in a unit volume of water.
The larger mass-to-volume ratio results in the increased density of the water.
Thus, the ocean water has a higher density at the equator than poles, due to temperature differences. Therefore, the given statement is false.
Learn more about surface water density, here:
brainly.com/question/2968053
Mud dries and changes to dust. A match stick turns to ash while burning. stomach acids dessolving pizza. grape juice fermenting into wine. an iron pipe rusting. when in doubt if something is chemical or physical, know that physical changes can be state changes like condensation, melting, evaporation, freezing, etc. If a leaf is cut up, it is still a leaf, no matter how many times you cut it. if whats happening is changing what it is made of its a chemical change. hope this helped :)
Answer : 0.125 M
Explanation : The definition of osmotic pressure is "<span><em>the pressure can be applied on a pure solvent to prevent it passing into a given solution by osmosis</em>".
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So according to this definition, osmotic pressure can be called as directly proportional to the concentration of the solution and hence the pressure can also be directly proportional to the concentration.
Hence, if pressure is getting decreased from 28 to 7 it means it got decreased by 4 times;
28 / 7 = 4 that means;
So the concentration will be also decreased by 4 times so, 0.50 / 4 = 0.125 M
Answer:
Number of moles = 0.042 mol
Explanation:
Given data:
Number of moles = ?
Mass of calcium carbonate = ?
Solution:
Formula:
Number of moles = mass/ molar mass
now we will calculate the molar mass of calcium carbonate.
atomic mass of Ca = 40 amu
atomic mass of C = 12 amu
atomic mass of O = 16 amu
CaCO₃ = 40 + 12+ 3×16
CaCO₃ = 40 + 12+48
CaCO₃ = 100 g/mol
Now we will calculate the number of moles.
Number of moles = 4.15 g / 100 g/mol
Number of moles = 0.042 mol
