Homework Help for Chemistry

The following carbohydrate shown is

◯ a. Disaccharides 

◯ b. Reducing 

◯ c. Non-reducing

◯ d. A and в 

◯ e. A and c

Balance the following redox reactions by the ion-electron method:

a.)     (acidic medium)

b.)    (acidic medium)

c.)    (acidic medium)

1. Which species are arranged in order of increasing entropy?

(1.5 points)

◯ (a) C3H8 (g) < CH3OH (l) 

◯ (b) CH3OH((l) < C3H8 (g)

◯ (c) Na+ (aq) < Hg(l)

◯ (d) Hg(l) < Na(s) 

b) If the initial concentration of is 0.150 M, what is the concentration of after 3.00 x seconds?

2) The decomposition of XY is second order in XY and has a rate constant of 7.02 x is at a certain temperature.

b) If the initial concentration of XY is 0.050 M, what is the concentration of XY after 3.50 x seconds?

 

b) How long will it take for the concentration of  is 25%?

c) How long will it take for 25.0% of of the to be isomerized?

9. Concentrated weak acid is best described as which of the following?

A. a solution with a low pH
B. a solution where the concentration of undissociated acid particles is low compared to the
concentration of hydronium ions
C. a solution where the concentration of hydronium ions is large compared to the
concentration of undissociated acid particles
D. a solution with a high pH
E. a solution where the concentration of undissociated acid particles is high and the relative
quantity of hydronium ions is small

8. Which condition is not a condition for an equilibrium system?

A. equal rates for opposing changes
B. a closed system
C. reactants in the same phase
D. constant temperature
Knowledge/Understanding: 8 marks

9. What is the Brønstead-Lowry definition of a base?
A. a substance that donates protons
B. a substance that accepts protons
C. a substance that dissolves in water to form OH
ions
D. a substance that dissolves in water to form H+
ions

10. What is the conjugate acid of H2PO4- (aq)?

A. H3O+(aq)
B. OH-(aq)
C. H3PO4(aq)
D. HPO4 2-(aq)
E. PO4 3- (aq)

11. What is the conjugate base of HSO4- (aq)?

A. H3O+(aq)
B. OH-(aq)
C. H2SO4(aq)
D. SO4 2-(aq)
E. This compound does not have a conjugate base.

12. What is the concentration of hydroxide ions in a solution of 0.350 mol/L HI(aq)?
A. 0.350 mol/L
B. 0.175 mol/L
C. 2.86 x 10^ -14 mol/L
D. 0.650 mol/L
E. 1.30 mol/L

13. A solution contains 3.25 x 10^ -8 hydroxide ions. What is the pH of the solution?
A. 3.25
B. 6.51
C. 7.49
D. 8.00
E. none of the above

14. Identify the weakest acid.
A. HCN Ka = 6.2 x 10^-10
B. HCOOH Ka =1.8 x10^-4
C. HNO2 Ka = 7.2 x 10^-4
D. HF Ka = 6.6 x 10^-4
E. All acids are the same strength, as long as they have a dissociable hydrogen ion.

A test give positive results only with starch

◯ a. lodine test 

◯ b. Benedict's test 

◯ c. Seliwanoff's test 

◯ d. Barfoed's test

How many mL of an 2.38 %% (w/v) solution can be prepared from 18.60 gg g of sucrose?

answer in mL please

a. Disaccharides 

◯ b. Reducing 

◯ с. Non-reducing 

◯ d. A and B 

◯ e. A and c

Which statement is true for carbohydrates? 

a. All polysaccharides are reducing sugars 

b. All monosaccharaides are reducing sugars 

c. All polysaccharides are non-reducing sugars 

d. All monosaccharaides are non-reducing sugars 

e. Both B and C 

f. Both A and D

The percent concentration of a solution is a ratio of the amounts of dissolved solute and solution, expressed as a percentage. The percent concentration of a solution can be written generally as

%concentration=amountofsoluteamountofsolution×100%%concentration=amountofsoluteamountofsolution×100%

Depending on the situation, a percent concentration might be calculated for mass/mass, volume/volume, or mass/volume.

1. Calculate the mass percent of a solution that is prepared by adding 31.4 gg of NaOHNaOH to 287 gg of H2OH2O.

Express your answer numerically.

2. Calculate the mass/volume percent of a NaClNaCl solution in which 200 gg of NaClNaCl is dissolved in enough water to give a total volume of 3.67 LL .

Express your answer numerically.

Present HPLC chromatogram of dicinnamalacetone

Show transcribed data

Which micropipettes pair you will use to prepare sample A in the table.

	Enzyme	Substrate	Buffer
Sample A	350	15	35
Sample B	350	75	200

◯ P-100 and P-200

◯ P-1000 and P-50

◯ P-100 and P-20

◯ P-1000 and P-10

◯ a. a monosaccharide

◯ b. a ketose 

◯ c. a hexose 

◯ d. all of these 

◯ e. A and C .

The value for △ for carbon dioxide in this reaction is:

◯ + 3120 kJ/mol

◯ - 3120 kJ/mol

◯ - 780 kJ/mol

◯ + 780 kJ/mol

Using the following information to answer the next question.

Chemists have prepared a new solvent. By adding a constant amount of heat energy to a fixed quantity of this solvent, they have collected enough data to plot a heating graph, shown below. This solvent has some very interesting properties.