Which of these amino acid side chains would be effective at carrying out covalent catalysis in an enzyme-catalyzed reaction at pH 7.4? Assume that if more than 10% of the side chain can act as a strong nucleophile, then there will be a sufficient amount of nucleophile available for the enzyme to perform covalent catalysis. Please select all possible answers. Lysine side chain with pKa = 9.0, where the positively charged state is destabilized by a nearby arginine side chain Glutamate side chain with pKa = 6.5, where the negatively charged state is destabilized due to the presence of a nearby Asp de chain Histidine side chain with pKa = 5.5, where the positively charged state is stabilized due to the presence of a nearby Asp side chain Alanine side chain

The mass of the original mixture was 2.03g. The combined mass of the salt and the evaporating dish was 48.92g with the tare mass of the evaporating dish being 47.98g. The combined mass of the sand and watch glass and filter paper was 32.15g with the tare mass of the watch glass being 30.91g and of the filter paper being 0.28g. 1A) calculate the mass of the table salt recovered. 2A) Calculate the mass of sand recovered 3A)calculate the total mass of table salt and sand recovered.  4A)Calculate the percent table salt in recovered material. 5A) calculate the table salt in the original mixture.

||| A ALEKS-Katelyn Pearson... 1 Apromatincat Rom Fecr] ATOMS, IONS AND MOLECULES Predicting the formula of ionic compounds with common... Write the empirical formula for at least four ionic compounds that could be formed from the following ions: OH, Fe²+, 103, NH b Answered. The following X O G

A 19.51 g sample of impure methylamine, which contains 72.58% (by mass) of CH;NH: , is reacted with 30.81 g of pure oxygen gas: 2.1 4CH, NH,(2) + 90,(8) - 4C0,(8) + 10H,0(?) + 2N;(8) 2.1.1 What is the percentage yield of this reaction if 5.54 g of nitrogen gas is collected? 2.1.2 In another experiment, this impure methylamine was used as follows: • An unknown mass of the impure compound is dissolved in enough water to make 500.0 m of solution. • 20 ml of this solution was transferred by pipette to a clean 250 ml volumetric flask and made up to the mark. • The molarity of the CH;NH; in the final solution was determined to be 0.103 M. Determine the mass of CH;NH; present in the original amount of impure compound used make this solution.

What mass of Cu(IO3)2 can be formed from 0.650 g of CuSO4 · 5H2O? What mass of KIO3 is needed to convert the copper in 0.2750 g of CUSO4 - 5H2O to Cu(IO3)2?

Calculate the mass of silver bromide produced from 23.2 g of magnesium bromide in the following reaction: 2AGNO;(aq) + MgBr,(aq) - 2AgBr(s) + Mg(NO)2(aq)

2. Calculate the following, with proper number of significant figures: Molar mass of Al(CH3COO)3 is g/mol In 16.4 moles of Al(CH3COO)3 ... ... the number of grams of Al(CH3COO)3 is the count of AlL(CH;COO); units is ... the number of moles of 6C atoms is mol ... ... the count of 6C atoms is ... the mass of 6C atoms is g The % mass fraction of 6C atoms in Al(CH;COO); is % The % mass fraction of Al atoms in Al(CH;coo)3 is % Name the compound:

no explanation needed, short answers appreciated

Riccardo states that the process of iron reacting with sulfur to produce iron(II) sulfide according to 16Fe + 3S8 = 8Fe2S3 16.00g of iron will react will 3.00 g of sulfur in the reaction. Do agree or disagree with this statement. Please explain.

If 136 g of BaCl₂ (FW 208.23 g/mol) is added to a solution containing 95.0 g of Na3PO4 (FW 163.94 g/mol), what mass, in g, of Ba3(PO4)2 (FW 601.92 g/mol) precipitate will be formed? The balanced equation is 3 BaCl₂(aq) + 2 Na3PO4(aq) → Ba3(PO4)2(S) + 6 NaCl(aq)