What massof Na2SO4 • 10H2O is needed to prepare a solution of Na2SO4(aq)
containing 1.5 × 10^20 anions? (Be sure to indicate the appropriate number of
significant figuresin the final answer.)

In what ways are the fuel supply and hormonal signals similar in untreated diabetes mellitus and starvation? In what ways are they dissimilar?

In Iodometric Analysis of Copper in Copper Oxide, why did I not need to accurately weigh out the KI used in the standard and unknown analysis?

Under what circumstances would we want to use a solvent pair for recrystallization instead of a single solvent? What can cause 'oiling out'?

Answer the following questions:

a. Define expansion work vs. non-expansion work.

b. Referring to the definition of the Gibbs energy (Eq. 6.9 in your text), show that dG represents the maximum amount of non-expansion work that a system can perform at constant T, and P.

c. Explain why G is referred to as a thermodynamic potential.

9A ) A 0.1752 g sample of solid primary standard AgNO3 was dissolved in water and titrated with 21.672 g of dilute KSCN solution. Calculate the weight molarity of KSCN solution?

whats the number of signifcant figures of each one?

2.46 × 2

714.3 - 18.56

29.3 ÷ (284 × 4.2)

485 ÷ 9.231

1.842 + 45.2 + 87.55

15.2 - 2.75 + 16.67

A 65.0 mL solution of 0.118 M potassium alaninate (H2NC2H5CO2K) is titrated with 0.118 M HCl. The pKa values for the amino acid alanine are 2.344 (pKa1) and 9.868 (pKa2), which correspond to the carboxylic acid and amino groups, respectively.

a) Calculate the pH at the first equivalence point.

b) Calculate the pH at the second equivalence point.

Consider the titration of a 24.0 −mL sample of 0.170 M CH3NH2 with 0.155 M HBr. Determine each of the following.

Part A the initial pH Express your answer using two decimal places. pH =

Part B the volume of added acid required to reach the equivalence point V = mL

Part C the pH at 6.0 mL of added acid Express your answer using two decimal places. pH =

Part D the pH at one-half of the equivalence point Express your answer using two decimal places. pH =

Part E the pH at the equivalence point Express your answer using two decimal places. pH =

Part F the pH after adding 6.0 mL of acid beyond the equivalence point

The mass of a 25.850g piece of copper is measured three times with two different balances with following results

Trial Method 1 (g)

1) 25.747

2) 25.745

3) 25.748

Trial Method 2 (g)

1) 25.70

2)25.75

3) 25.71

c. Calculate the % error for each method. method 1 _________ method 2 _________ Which method is more precise? Explain your answer.

Thank you

An anctacid tablet was dissolved in 26.00ml of 0.650M HCl. The excess acid was back titrated with eactly 11.34ml of 1.05M NaOH. The average weight of a tablet is 0.834g. The tablet came from a bottle 150 tablets that cost $3.99.

a. Calculate the moles of HCl neutralized by the tablet. (moles of HCl(aq) neutralized per tablet = moles of HCl(aq) added to the antacid - moles of NaOH required to backtitrate)

b. Calculate the mass effectiveness of the antacid. (mass effectiveness = moles of HCl(aq) neutralized per tablet / mass of antacid (g))

c. Calculate the cost effectiveness of the antacid. (cost effectiveness = moles of HCl(aq) neutralized per tablet / price of tablet (cent))

An older naming system uses Latin names of the elements. For example, the Latin name of iron is ferrum (which gives iron its symbol of Fe). For metals that can have more than one charge, the Latin name takes a –ous ending for the smaller charge and an –ic ending for the larger charge. Based on these rules, what is the Latin name of Fe22​O33​?

A Ferrous oxide

B Ferric oxide

C Ferrum oxide

D Iron oxide

Aluminium oxide is a white , crystalline powder . it can be used as an adsorbent or a catalyst for organic reactions and is formed when aluminium reacts with oxygen . A mixture of 74.38g of Aluminium and 56.27 g oxygen gas is allowed to react.
...
1) write a balanced equation for the reaction above.
...
2) identify the limiting reactanct by showing the calculation .
..
3)determine the mass of the excess reactant present in the vessel when the reaction is complete.

1.What is the coordination number for each of the following complexes?

[Co(NH3)4Cl2]+

[Pb(EDTA)]2?

[Cu(NH3)4]2+

[Ag(NH3)2]NO3

2.What is the charge on each of the following complex ions?

hexaaquachromium(II), [Cr(H2O)6]?

tris(carbonato)ferrate(III), [Fe(CO3)3]?

diaquatetrabromovanadate(III), [V(H2O)2Br4]?

3.What is the oxidation number of the central metal ion in each of the following complexes?

[NiCl2Br2]2?

[Fe(H2O)2(NH3)4]3+

Na[Rh(CN)2]

The main defect in stoichiometric CsI is the Schottky defect. The fraction of lattice sites that exhibit Schottky defects as a function of temperature, is as follows: 1.08 x 10exp-16 at 300 K, 1.06 x 10exp-12 at 400 K, 2.63 x 10exp-10 at 500K, 1.04 x 10exp-8 at 600 K, 4.76 x 10exp-6 at 900 K. Show whether the formation of Schottky defects is given by an Arrhenius (or Boltzmann) expression and, if so, evaluate the enthalpy of formation of one Schottky defect and 1 mol of Schottky defects.