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A colloid is a substance in which microscopic particles are dispersed in a medium, but are not dissolved in it. ... A suspension is similar to a colloid except that the dispersed particles tend to be larger and will eventually settle or form sediment.

Hello!

What is the mass percent of Hydrogen, H, in resveratrol? Select one: a. 5.31% b. 5.26% c. 19.02% d. 18.83%

We have the following data:

Solving:  

[First step]  Identify the compound:

The Resveratrol compound has the following molecular formula 

[Second step]  Identify Molar Mass (MM) of Resveratrol:

molecular weight of the element in the compound = number of elements (n) *  molecular weight

C = 14*(≈12.01u) ≈ 168.14 u

H = 12*(≈1.01u) ≈ 12.12 u

O = 3*(≈16u) ≈ 48 u

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[Third step] Now, we apply the data to the percentage composition formula of an element:

What is the mass percent of Hydrogen, H, in resveratrol ? Let's see:

a. 5.31%

The percentage of hydrogen in Resveratrol is approximately 5.31 %  

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Hello!

5.58 g iron reacted with 3.21 g sulfur. How many grams of iron sulfide were produced ?

We have the following data:

m(Fe) - mass of iron = 5.58 g

m(S) - mass of sufur = 3.21 g

MM(Fe) - molar mass of iron ≈ 56 g/mol

MM(S) - molar mass of sulfur ≈ 32 g/mol

n(Fe) - number of mol of iron = ?

n(S) - number of mol of sulfur = ?

Solving:

* to n(Fe)

* to n(S)

The stoichiometric reaction will be in the same proportion (1 : 1), let us see:

1 mol of Fe -------------- 1 mol of FeS

0.1 mol of Fe ------------ 0.1 mol of FeS

Will the reaction of the iron mass with the mass of sulfur produce how many grams of iron sulfide? We will see:

n(FeS) - number of mol of iron sulfide = 0.1 mol

m(FeS) - mass of iron sulfide = ? (in grams)

MM(FeS) - Molar Mass of iron sulfide = 56 + 32 = 88 g/mol

Solving:

8.8 grams of iron sulfide

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   At

one time, oysters were so abundant in the Chesapeake Bay that their reefs

defined the major river channels. The reefs extended to near the water surface;

to stray out of the center channel often posed a navigational hazard to ships

sailing up the Bay. Now, after decades of damage to reefs from harvest,

increased disease, falling salinity due to the increased runoff that

accompanies increased impervious surface, and increased sedimentation from

runoff, a significant amount of hard bottom habitat has been lost. The oyster

population in the Bay is less than 1% of what it once was.

    Degrading water quality is both a cause

and an effect of the oyster decline, because fewer oysters means less

filtration capacity. But oysters, as hardy as they are, can be killed by

prolonged periods of low dissolved oxygen at the Bay's bottom.