21 Questions
Why do colloidal suspensions not coagulate spontaneously?
Colloidal particles have a high surface-to-mass ratio, which promotes surface adsorption.
What is the main function of coagulation in dealing with colloids?
To prevent settling out of colloidal particles from the solution.
What happens when enough silver nitrate is added to a solution containing chloride ions?
The colloidal particles become negatively charged.
Why are colloidal particles not retained by ordinary filters?
Their small size makes them pass through filter pores.
In gravimetric calculations, what is the aim when dealing with precipitates?
To determine the weight of the analyte from the weight of precipitate.
What is the SI unit for the amount of a chemical substance?
Mole
Which formula gives the simplest whole number ratio of atoms in a chemical compound?
Empirical formula
What is the molar mass of Fe2O3 (Iron (III) oxide)?
159.69 g/mol
How many moles of Hydrogen gas are there in 27g of H2?
13.4 moles H2
What is the percent composition of Nitrogen in Mg(NO3)2?
18.89%
What is the formula weight of MgCl2?
95.21 amu
What does the empirical formula of a compound indicate?
The relative numbers of atoms of each element in the compound
If a compound contains 60% oxygen and 40% sulfur by mass, what is its empirical formula?
SO3
In stoichiometric calculations, what do balanced chemical equations provide?
Combining ratios of reactants and products in moles
If a compound contains 72% Mn, what is the remaining element present?
Oxygen
What is the total number of carbon atoms in 5×10^-5 mole of CO2?
$3.01 × 10^{19}$
What is the unit used to express stoichiometry in balanced chemical equations?
Moles
In stoichiometric calculations, what factor is multiplied by the number of moles to account for stoichiometry?
$6.02 × 10^{23}$ (Avogadro's number)
What is the role of a three-step stoichiometric calculation in a chemical reaction?
Relating the masses of reactants and products
$40$ grams of a compound contain $1.25$ moles of sulfur. What is the molar mass of sulfur?
$32$ g/mol
$0.0022$ gram of CO2 corresponds to how many moles of CO2?
$5 × 10^{-5}$ moles
Explore the properties of individual colloidal particles, including their small size which prevents retention by ordinary filters, and how Brownian motion prevents settling out of solution. Learn about coagulation and agglomeration processes in colloids.
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