What amount of heat (in kJ) is required to convert 10.1 g of an unknown solid (MM = 67.44 g/mol) at -15.4 °C to a liquid at 42.7 °C? (heat capacity of solid = 1.95 J/g･°C; heat capacity of liquid = 1.18 J/g･°C; ∆Hfus = 5.72 kJ/mol; Tf = 28.3°C)

Until roughly 1970, tritium (3H), a radioactive isotope of hydrogen, was a component of fluorescent watch dials and hands. For 3H, t1/2 = 12.3 yr. Assume you have such a watch. If a minimum of 12.0% of the original tritium is needed to read the dial in dark places, for how many years could you read the time at night? Assume first-order kinetics.

Calcium carbide crystallizes as a cube with 1 calcium ion on each corner and one calcium ion in the center of the cell. There are 8 carbon atoms located along edges of the cell and there are two carbons internal to the cell. What is the formula of calcium carbide?

Ca₂C₃

CaC₄

CaC₃

CaC₂

CaC

in the following arithmetic operation when carried out, how many significant figures should be reported in the answer and why? (0.523)(1.2161-0.99)+(2.648/0.87)(84-81.98)

At 1024°C, the pressure of oxygen gas from the decomposition of copper(II) oxide (CuO) is 0.490 atm: 4CuO(s) ⇆ 2Cu2O(s) + O2(g)

(a) What is KP for reaction?

(b) Calculate the fraction of CuO decomposed if 0.860 mole of it is placed in a 2.00 L flask at 1024°C.

(c) What would be the fraction if a 1.00 mole sample of CuO were used?

Can someone please help me with part B and C

I make threesaturated solutions of AgCl (Ksp= 1.8•10-10). The first is in pure water, the second is in 0.01 M KNO3, and the third is in 0.01 M NaCl. I measure the concentration of Ag+in each solution. Which has the highest Ag+concentration? Which has the lowestAg+ concentration? Please explain why there are differences in concentrations between the solution with the highest and lowest concentrations. I’m not asking for the actual concentration, so you don’t need to do any math.highest: _________________________________lowest: _________________________________why:

1. A solution was prepared by mixing 6.00 mL of 1.00M NaOH with 40.00 mL of 0.800M weak acid and diluting to a total volume of 100.0 mL. The pH value of this solution was measured to be 3.12. Calculate the equilibrium hydrogen ion concentration of this solution using the pH value.

2. For the solution from question 1, calculate the number of moles of weak acid and calculate the number of moles of hydroxide ion that were originally present.

3. Calculate the number of moles of weak acid and calculate the number of moles of conjugate base present at equilibrium.

4. Calculate the concentrations of weak acid and conjugate base present at equilibrium.

5. Calculate the value of Ka for the unknown weak acid.

Out of idle speculation, you drop a metal ball from a height of 2 yards onto a sample cute from a plastic sheet. (You are an old-fashioned engineer and can have no truck with units such as meters.) You observe that the plastic sheet punctures in a ductile fashion, leaving a hole roughly the size of the ball. You find that if the same metal ball is dropped onto another sample of the same plastic sheet from a height of 4 yards, the sample shatters in a brittle manner. How would you explain these observations?

Test tubes 1-8 contain the following amounts of 0.05M [KI] and 0.002M [I2]. The absorbance of the solutions were then measured at a wavelength of 430nm. Calculate the final [I2].

Which one of the salts below is least soluble at 25^oC?

Group of answer choices

MnS, K_sp = 2.3x10^-13

PbCO₃, K_sp = 1.5x10^-15

AgCN, K_sp = 1.2x10^-16

SrCO₃, K_sp = 7.0x10^-10

Define the following terms: [3 marks] a) Titrant: __________________________________________________________________________________________________________________________________________________________________________________________

b) Titrand: __________________________________________________________________________________________________________________________________________________________________________________________

c) Concordant Titre:

........................................................................................................................................................................................

Give the reason why you should [2 marks]
a) Never blow out the small amount of solution left at the bottom of a pipette.
__________________________________________________________________________________________________________________________________________________________________________________________
b) Keep the NaOH solution stoppered at all times when it is not in use
__________________________________________________________________________________________________________________________________________________________________________________________
3. 23.6cm3 of H2SO4 neutralised 25cm of 0.150M NaOH. What is the concentration of the H2SO4? [5 marks]__________________________________________________________________________________________________________________________________________________________________________________________

In addition to cyclopentadienyl, indenyl and fluorenyl can also act as η5 ligands. For which η5-ligand would you expect that the substitution of (η5-ligand)Mn(CO)3 with P(n-Bu)3 to occur the fastest? slowest? (Hint: A review by Casey in 1987 may help)

Those are three substances: Ferrocyanide (Fe(CN)64-); Ferrocenemethanol; Fe2+(aq).

The question is: Based on the understanding of Marcus Theory and how it is used to rationalize the observed rate of electron transfer for redox species, draw out the shape of the CV that will be obtained for each of the Fe(II) species.