"CHEM JUST" 107 Mid-Term Exam ( Created By : Omar Kofahi )

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CHEM JUST 107 Mid-Term Exam

Welcome to the CHEM JUST 107 Mid-Term Exam! This quiz is designed to assess your understanding of fundamental chemistry concepts, practical applications, and problem-solving skills.

Prepare yourself with a variety of questions that cover key topics such as:

Chemical reactions
Quantitative analysis
Laboratory techniques
Properties of substances
Understanding of gaseous reactions

21 Questions5 MinutesCreated by ChemistryNinja42

Which of the following glass wares could be used for heating a mixture :

Buchner funnel

Test tube

Evaporating dish

Graduated cylinde

7.896g of Ca3(PO4)2 (MM=310) was reacted with excess HCL according to Ca3(PO4)2 + 2HCL ----------> Ca(H2PO4)2 + 2CaCl2 If 3.245g of Ca(H2PO4)2 (MM=234) were produced the the percent yield is :

35.35

36.5

66.5

54.45

Degree of agreement of measured values with the true values is defined as

Precision

Accuracy

Vinegar

Non of above

Calculate the freezing point of a solution made by dissolving 30 g of ethylene glycol (MM=62g/mol) in 70g of water (Tf = 0Cْ , Kf = 1.86 c/m) :

-24.5 Cْ

-12.9 Cْ

-12.5 Cْ

25.4 Cْ

H2 gas could be evolved through the addition of :

Strong acid to table salt

Hot water to drain opener

Strong base to fertilizer

Non of above

The density of Oil was calculated to be 0.875 g/cm^3 at 25 Cْ the mass (mg) of 6.3 dm^3 of Oil sample is (use correct S.F) :

5.5 × 10^-6

5.52 × 10^-6

5.5 × 10^6

Non of above

How many moles of NO2(g) could be produced through the reaction of 0.20 moles of NO with 0.30 moles O2 according to the following equation NO(g) + 1/2 O2(g) ----------> NO2 (g)

0.30

0.20

0.40

0.60

A mixture of BaCl2.2H2O and Na3PO4.10H2O weighting 8.77g was dissolving in distilled water and heated 2.33g of Ba3(PO4)2 was precipitated according to 2PO4^-3 + 3Ba^+2 -------> Ba3(PO4)2 .......... If PO4^-3 is th limiting reactant then the mass percent of the excess reactant in the mixture is :

When 2.0g of aluminum (At Mass = 27 g/mol) is reacted completely with excess HCL , it given 4..6g of AlCl3 (MM = 133.5g/mol) The percent yield of this reaction is : 2Al + 6HCL -----> 2AlCl3 + H2

The limiting reactant is :

The reactant that has the smallest number (of moles)

The reactant that has the largest number (of moles)

Non of above

The percent that has the smallest mass

Solid NaCl can be separated from solid NH4Cl by dissolving the mixture in water then heating the mixture

True

False

A mixture containing 0.5g of SiO4 , 20% (wt/wt) , NaCl and unknown amount of NH4Cl, when the mixture was heated , it's mass was decreased to 1.0g , The mass of NH4Cl in the mixture is :

1.5g

2.5g

3.5g

4.5g

When concentrated H2SO4 was added to solid unknown ,colorless and odorless bubbles was evolved the unknown could be

NaCl

Na2SO4

NaI

Na2CO3

X + 2HCl ----> Y + 2HNO3 ,,,,,,,,,,,,,,,,, Y + 2NH3 -------> Hg + Z + NH4Cl In above equation : X and Z respectively are :

Hg2Cl2 , HgNH2Cl

Hg2(NO3)2 , Hg2Cl2

Hg2Cl2 , Hg2(NO3)2

Hg2(NO3)2 , HgNH2Cl

As the amount of solute added to solution decrease

Freezing point will decrease

Boiling point will decrease

Vaper pressure will decrease

Osmotic pressure will increase

"CHEM JUST" 107 Mid-Term Exam ( Created By : Omar Kofahi )

CHEM JUST 107 Mid-Term Exam

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