Answer:
320 g
Step-by-step explanation:
The half-life of Co-63 (5.3 yr) is the time it takes for half of it to decay.
After one half-life, half (50 %) of the original amount will remain.
After a second half-life, half of that amount (25 %) will remain, and so on.
We can construct a table as follows:
No. of Fraction Mass
half-lives t/yr Remaining Remaining/g
0 0 1
1 5.3 ½
2 10.6 ¼
3 15.9 ⅛ 40.0
4 21.2 ¹/₁₆
We see that 40.0 g remain after three half-lives.
This is one-eighth of the original mass.
The mass of the original sample was 8 × 40 g = 320 g
Answer : The compound that would be most soluble in water is CH3CH2CH2OH
Explanation :
Water is a polar solvent and can dissolve polar molecules. This is based on the principle "Like dissolves like".
Among the given molecules, CH3CH2CH2CH3 is a hydrocarbon known as butane. All hydrocarbons are non polar. Therefore this compound will not be soluble in water.
The remaining compounds are polar, but Ch3CH2CH2OH shows greater solubility in water owing to presence of hydrogen bonding.
Hydrogen bonding is a type of intermolecular force that gets formed when a compound has hydrogen atom directly attached to highly electro-negative N, F or O atom.
When CH3CH2CH2OH is dissolved in water, it forms hydrogen bonds with water molecules. Due to this hydrogen bonding, the molecule shows greater solubility.
Therefore CH3CH2CH2OH is the most soluble compound in water
Malleability described the property of physical deformation under some compressive stress; a malleable material could, for example, be hammered into thin sheets. Malleability is generally a property of metallic elements: The atoms of elemental metals in the solid state are held together by a sea of indistinguishable, delocalized electrons. This also partially accounts for the generally high electrical and thermal conductivity of metals.
In any case, only one of the elements listed here is a metal, and that’s copper. Moreover, the other elements (hydrogen, neon, and nitrogen) are gases under standard conditions, and so their malleability wouldn’t even be a sensible consideration.
Answer:
<em>Friction between the hand and the wood decreased.</em>
Explanation:
The texture of the wood went from rough → smooth! This means friction between the hand and the wood was notably decreased.
According to this prompt, the carpenter used <em>sandpaper </em>against the wood. Sandpaper just so happens to be a very abrasive substance. The sandpaper polished and leveled out the wood which wore all the jutting bits away.- overall, making it much smoother and more pleasant to touch!
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