Every compound or element has a fixed number of molecules
per mole. This is given by the Avogadros number which is about 6.022 x 10^23
molecules per mole. Therefore:
molecules = 2.50 moles * (6.022 x 10^23 molecules / mole)
<span>molecules = 1.5055 x 10^24 molecules of SO2</span>
<span>There are pros and cons as to whether CCA-treated (pressure-treated) wood should be removed from existing structures, and both sides are subjective.
Some of the arguments for leaving it include:
*When burned, the wood can release dangerous, and sometimes, lethal fumes.
*If buried in a landfill, the chemicals can soak into the ground and eventually contaminate ground water.
*Removing it can expose people to arsenic
*It is costly to remove an existing infrastructure that may or may not be harming people
*Studies conducted within the past decade have determined structures containing CCA-treated wood pose no hazard
*Studies also concluded that children who played on CCA-treated playgrounds were exposed to arsenic levels lower than those that naturally occur in drinking water
Some of the arguments for removing it include:
*The EPA determined that some children could face higher cancer risks from exposure to CCA-treated wood
*If removed, it will need to be disposed of and, as discussed above, that creates another set of problems that could affect a community's health.
A possible solution is to leave existing CCA-treated wood in place but seek viable, safe alternatives for future structures.</span>
We are given that the balanced chemical reaction is:
cacl2⋅2h2o(aq) +
k2c2o4⋅h2o(aq) --->
cac2o4⋅h2o(s) +
2kcl(aq) + 2h2o(l)
We known that
the product was oven dried, therefore the mass of 0.333 g pertains only to that
of the substance cac2o4⋅h2o(s). So what we will do first is to convert this
into moles by dividing the mass with the molar mass. The molar mass of cac2o4⋅h2o(s) is
molar mass of cac2o4 plus the
molar mass of h2o.
molar mass cac2o4⋅h2o(s) = 128.10
+ 18 = 146.10 g /mole
moles cac2o4⋅h2o(s) =
0.333 / 146.10 = 2.28 x 10^-3 moles
Looking at
the balanced chemical reaction, the ratio of cac2o4⋅h2o(s) and k2c2o4⋅h2o(aq) is
1:1, therefore:
moles k2c2o4⋅h2o(aq) = 2.28
x 10^-3 moles
Converting
this to mass:
mass k2c2o4⋅h2o(aq) = 2.28
x 10^-3 moles (184.24 g /mol) = 0.419931006 g
Therefore:
The mass of k2c2o4⋅<span>h2o(aq) in
the salt mixture is about 0.420 g</span>
An aqueous solution of potassium sulfate exhibits colligative properties. Colligative properties are properties that depends on the concentration of a substance in a solution. These properties are freezing point depression, vapor pressure lowering, osmotic pressure and boiling point elevation. For this problem we use the concept of freezing point depression since we are given the freezing point of the solution. Freezing point depression is as:
ΔT = -k(f) x m x i
-2.24 - 0 = -1.86 x m x 3
<span>m = 0.4014
Thus, the molality of the solution is 0.4014.</span>
Answer:
Explanation:
The formula for efficiency is
Data:
Useful energy = 3 J
Energy input = 30 J
Calculation:
