what is heavy metal contamination

Construct a curve for the titration of 50.00 mL of a 0.1000 M solution of ethylenediamine with a 0.2000 M solution of HCl in the following table. For each titration, calculate the pH after the addition of 0.00, 12.50, 20.00, 24.00, 25.00, 26.00, 37.50, 45.00, 49.00, 50.00, 51.00, and 60.00 mL of HCl.

A mixture of 8-hydroxyquinoline complexes of aluminum and magnesium weigh 1.0843 g. When ignited in a furnace open to the air, the mixutre decomposed, leaving a residue of Al2O3 and Mg weighing 0.1344. What is the weight percent of Al(C9H6NO3) in the original mixture? AlQ3 + MgQ2 ? Al2O3 + MgO

How many of the following responses are true?

1. 3-bromo-3-methylpentane will undergo substitution through an S_N2 mechanism
2. If R-2-bromopentane is allowed to react with OH^- the product will be S-2-pentanol
3. S_N1 leads to a racemization of sterechemistry due to the nucleophile attacking from the backside and the leaving group leaving
4. S_N2 leads to a racemization of sterechemistry due to the nucleophile attacking from the backside and the leaving group leaving
5. A primary alkyl halide will tend to react through an S_N2 mechanism because there is little hindrance to backside attack and a primary carbocation is not very stable

ITEM 17 The decomposition of NH4HS is endothermic:
NH4HS(s)?NH3(g)+H2S(g)

Which change to an equilibrium mixture of this reaction results in the formation of more H2S?

Which change to an equilibrium mixture of this reaction results in the formation of more ?

why is H2O2 added to the precipitate of Fe(OH)3 and Cr(OH)3?

Gasoline is primarily a mixture of hydrocarbons and is sold with an octane rating that is based on a comparison with the combustion properties of isooctane. Gasoline usually contains an isomer of isooctane called tetramethylbutane (C8H18), which has an enthalpy of vaporization of 43.3 kJ/mol and a boiling point of 106.5°C. Determine the vapor pressure of tetramethylbutane on a very hot summer day when the temperature is 38°C.

A. 47.9 torr
B. 67.8 torr
C. 89.3 torr
D. 80.3 torr
E. 36.7 torr

Air (consisting mostly of nitrogen (N2), oxygen (O2), and argon (Ar)) dissolves in water due to?

A. dipole-induced dipole forces.
B. ion–dipole forces.
C. dipole–dipole forces.
D. hydrogen bonding.
E. dispersion forces.

Thanks!

What symbolism do you find in the play,Oedipus?

Consider a buffer system consisting of Benzoic acid (pKa = 4.20) and sodium benzoate,

a) Would this buffer system be an appropriate choice to maintain a pH of 8.5? ues or no

b) To produce a buffer with a pH = 4.55, what mass of sodium benzoate (FM = 104.10) must be dissolved in 500 mL of 0.65 M benzoic acid?

c) What is the resulting pH if 45-mL of 0.08-M HCl is added to 250 mL your buffer?

A 19.34 g mixture of sugar (C12H22O11) and table salt (NaCl) is dissolved in 231 g of water. The freezing point of the solution was measured as -3.84 °C. Calculate the mass percent of sugar in the mixture. Use a list of Kf values.

explain why Tm in HDPE is higher than Tg in comparison to PET and PE
HDPE Tm>>>Tg
PET    Tm >>Tg
PE      Tm>Tg

tm: melting temperature of a polymer
tg=glass transition temperature

Try to solve these problems using the Table method

3. Combustion analysis was performed on 1.50 g of a compound containing C, H and N to yield 3.21 g of carbon dioxide and 0.981 g of water. What is the empirical formula of this compound?

4. A 3.82-g sample of magnesium nitride is reacted with 7.73 g of water. Mg3N2 (s) + 3 H2O (ℓ) → 2 NH3 (g) + 3 MgO (s) The yield of MgO is 3.60 g. What is the percent yield in the reaction?

5. a) A beaker contains 200.0 mL of 0.250 M AgNO3. 200 mL of 0.100 M HCl(aq) is added to it. What is the NO3 − concentration in the final mixture?

b) What is the Ag+ concentration in the final mixture?

Please explain why

How do you determine the active center of a monomer/molecule?

a hydrogen atom is in the 2p state. How much time must elapse for there to be a 1.3 % chance that this atom will undergo a quantum jump to the ground state?