What do tyrosinase inhibitors do?
What is the importance of tyrosinase and tyrosinase inhibitors in the food industry?

In the citric acid cycle, malate is oxidized to oxaloacetate by the enzyme malate dehydrogenase, which uses NAD+ as an electron acceptor. In cells, the ratio of [NAD+]/[NADH] is kept very high. Given the following standard reduction potentials, explain why it is so important for cells to maintain this ratio. Justify your answer with words, equations and diagrams.

oxaloacetate + 2H+ + 2e- -> malate

E°red= -0.166 V

NAD+ + H+ + 2e- > NADH

E°red= -0.320

You are considering options for a deposition process for a-Si that gives acceptable quality films and is able to deposit 5 nm thickness in less than a minute. Compare the HW PECVD, VHF PECVD and RFCVD in terms of the required output.

Nitrogen and hydrogen combine at high temperature, in the presence of a catalyst, to produce ammonia.

N2(g)+3H2(g)-->2NH3(g)

Assume 0.210 mol N2 and 0.664 mol H2 are present initially.

1.)After complete reaction, how many molecules of ammonia are produced?

2.How many molecules of H2 remain?

3.How many molecules of N2 remain?

4.What is the limiting reactant, Hydrogen or Nitrogen?

How many milliliters of 0.100 M NaOH are required to neutralize the following solutions?

(a) 8.00 mL of 0.0500 M HCL

(b) 20.00 mL of 0.126 M HNO3

(c) 45.00 mL of 0.215 M H2SO4

How many milliliters of 0.100 M HNO3 Are needed to neutralizw the following solutions

34.7 mL of 0.775 M Naoh _____mL

58.5 mL of 0.0100 M Al(OH)3 ____mL

* Predict solubility based on hydrogen bonding interactions

Predict electron distribution in a bond from electronegativity

Define the chemical basis of hydrogen bonding.

Identify and construct hydrogen bond donor and acceptor groups

Predict hydrogen bonding potential among various functional groups

Relate hydrogen bonding with solvent water to solubility

At a certain temperature and pressure an element has the simple body-centred cubic unit cell, depicted below. The corresponding density is 8.597 g cm-3 and the atomic radius is 1.428 Å. Calculate (and enter) the atomic mass for this element (in amu).

Question 1

a)velocity of an electron emitted by a metal whose threshold frequency is 2.24×10¹⁴ s−1s−1 when it is exposed to visible light of wavelength 5.14×10⁻⁷ mm .

Find the Velocity

b)What is the de Broglie wavelength of an electron traveling at 1.61×10⁵ m/sm/s?

Find de Broglie wavelength

Methanoic acid has a Ka=1.6X10-4. Calculate the pH of the final solution when 23.90 mL of 0.100M NaOH is added to 25.00 mL of 0.100 M methanoic acid

calculate the pH at the equivalence point of a titration of 0.3326 g THAM pKa 5.92 dissolved initially in 25 mL of H2O with 0.1042 M Hcl please show step by step

Calculate the PH of the following solutions

a) 25g HCIO4 in 500ml aqueous solution

b) 0.2M hydrofluoric acid

c) 0.02M Ca(OH)2

d) 25g HCIO and 30g Ca(CIO)2 in 1000ml aqueous solution

For each process, state whether ΔG_sys, ΔH_sys, and ΔS_sys are positive, negative or zero.

a. An ideal gas is compressed in one step from 1 atm to 5 atm a constant temperature.

b. Water freezes at its normal freezing point.

c. Benzene dissolves in toluene.

12. Define terms system and surroundings. What does it mean to say a system and its surroundings are in thermal equilibrium?

What determines the directionality of energy transfer as heat?

8. Here we are going to consider the differences between spectra and chromatograms. A list is given below of characteristics and behaviors of UV spectra and liquid chromatography. Some characteristics listed apply only to spectra. Other characteristics apply only to chromatography. And here’s the tricky bit, some characteristics apply to both. From the list below enter each characteristic that is correct for that instrumental plot on the line associated with that instrumental plot. Be careful, think about your choices, misplaced characteristics are negative points.

1. Usually has molar absorptivity values reported in homogeneous liquid solution

2. In our work in this lab, the solvent system is the eluent

3. Spans the UV and visible regions of the electromagnetic spectrum

4. Can be used for analytical work

5. Displays radiation absorption by molecules in solution

6. Displays the retention/separation by an appropriate stationary phase of molecules in solution

7. Provides information about how molecules are distributed between mobile and stationary phases

8. Can be used to identify unknown components in samples

9. Has time as the independent variable on the detector output plot

10. Has wavelength as the independent variable on the detector output plot

11. Has absorbance as the dependent variable on the output plot

12. Is concerned with electronic transitions in molecules

13. Is concerned with molecular distribution between phases

14. May show the instrument output plot at a constant flow rate

A. Liquid Chromatography plot characteristics are: _______________

B. UV spectral plot characteristics are: ________________

2. For the diprotic weak acid H2A, Ka1 = 2.7 × 10-6 and Ka2 = 8.8 × 10-9. What is the pH of a 0.0500 M solution of H2A? What are the equilibrium concentrations of H2A and A2– in this solution?