Answer:
A manually-operated lawn mower needs a lot of force to move. The mower mechanism and the energy needed to cut through the grass causes a lot of friction. In order to cut the grass faster, you need to overcome all that friction and get a net positive force on the lawn mower. Thus, you need to apply more force to it. It also helps a lot to reduce friction, so oil the mower and keep the blades sharp.
Explanation:
This is exact words on PLATO so use your own words!
Answer:
1)1.61molKg-1
Explanation:
we find the molality using the formula mole of solute/Kg of solvent..
Answer:
The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell. When atoms have fewer than eight electrons, they tend to react and form more stable compounds. When discussing the octet rule, we do not consider d or f electrons.
Explanation:
Answer:
C. the carbons in ethene are linked by double bonds
Explanation:
The reason for the lack of free rotation about the carbons of ethene is that they are linked with with double bonds.
In single bonds afforded with the ethane compound, there is free rotation.
The double bonds confer a special restriction on the rotational potential of the bonded atoms round the carbon.
Answer:
1.2 M
1.2 m
Explanation:
There is some info missing. I think this is the original question.
<em>A student dissolves 5.1g of ammonia (NH₃) in 250 mL of a solvent with a density of 1.02 g/mL. The student notices that the volume of the solvent does not change when the ammonia dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to 2 significant digits.</em>
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Molarity
The molar mass of ammonia is 17.03 g/mol. The moles corresponding to 5.1 grams is:
5.1 g × (1 mol/17.03 g) = 0.30 mol
The volume of the solution is equal to the volume of the solvent, 250 mL or 0,250 L.
The molarity of ammonia is:
M = moles of solute / liters of solution
M = 0.30 mol / 0.250 L
M = 1.2 M
Molality
The density of the solvent is 1.02 g/mL. The mass corresponding to 250 mL is:
250 mL × 1.02 g/mL = 255 g = 0.255 kg
The molality of ammonia is:
m = moles of solute / kilograms of solvent
m = 0.30 mol / 0.255 kg
m = 1.17 m ≈ 1.2 m