4. Cr has four isotopes:

Cr 50

Cr 52

Cr 53

Cr 54

A) Determine how many protons, neutrons and electrons each isotope has.

B) The atomic mass reported for Cr is 54.94. What does this tell us about the relative abundance of each isotope? What isotope should be the most abundant?

C) Write the electronic configuration of the Cr, taking into account that studies show that it has a paramagnetism equivalent to 6 unpaired electrons. Determine the quantum numbers for the last electron 4s of Cr.

D) Determine the effective nuclear charges for the following Cr electrons:

---An electron 4s
---A 3d electron

Please try to write everything in an organized maner and legible handwritting.

The formation of tetrafluoroethylene from its elements is highly exothermic:

2F2(g) + 2C(s) ↔ F2C=CF2(g)

(a) If a mixture of F2, graphite, and C2F4 is at equilibrium in a closed container, will the reaction go to the right or to the left in F2 is added?

(b) Rare bacteria from the planet Teflon eats C2F4 and make Teflon for their cell walls. Will the reaction go to the right or to the left if these bacteria are added?

(c) Will the reaction go right or left if solid graphite is added? (Neglect any effect of increased pressure due to the decreased volume in the vessel when solid is added.)

(d) Will the reaction go right or left if the container is crushed to one-eight of its original volume?

(e) Does the equilibrium constant become larger or smaller if the container is heated?

what is the maximum mass (in grams) of each of the following soluble salts that can be added to 160 mL of 0.050 M BaCl₂ without causing precipitate to form? (assume the addition of solid causes no change in volume).

a. (NH₄)₂SO₄

b. Pb(NO₃)₂

c. NaF

Determine the pH during the titration of 33.6 mL of 0.295 M methylamine (CH3NH2, Kb = 4.2×10-4) by 0.295 M HClO4 at the following points. (Assume the titration is done at 25 °C.) Note that state symbols are not shown for species in this problem.

(a) Before the addition of any HClO4

(b) After the addition of 12.4 mL of HClO4

(c) At the titration midpoint

(d) At the equivalence point

(e) After adding 49.1 mL of HClO4

Explain how polarity P' is related to retention of the sample analytes on the silica column for both the normal-phase and reverse-phase procedures.

Identify the number of core and valence electrons for each atom. Xe : core electrons Xe : valence electrons Be : core electrons Be : valence electrons Br : core electrons Br : valence elect.

1. Benzene [C6H6] and toluene [C7H8]  form a solution that is nearly ideal. At 30 ℃ the vapor pressure of an excess of pure benzene is 120.2 mmHg and that of toluene is 36.7 mmHg.
   a) What is the total pressure of a mixture containing 100 g of each?
   b) What is the percent of benzene in the mixed vapors?

Consider the reaction A -> 2 B. Initially 1.50mol A is present and no B. What are the amounts of A and B when the extent of reaction is 0.60mol?

Identify the Bronsted acid and base in each of the following equations: Please show all work on how you got the answer so I can understand.

HNO₃ + H₂O

Iron (III) oxide reacts with carbon monoxide to produce iron and carbon dioxide:

Fe2O3 (s) + 3CO(g)  2Fe (s) + 3 CO2 (g)

54.4 g of Fe2O3and 24.7 g of CO react to produce iron.

Molar mass of Fe2O3 = 159.69 g/mol. Molar mass of CO = 28.01 g/mol.

Determine the (a) limiting reactant, (b) theoretical yield, and (c) percent yield for the reaction if 29.1 g of iron are produced.

If a 0.100 M solution of NaOH is added to a solution containing 0.200 M Ni²⁺, 0.200 M Ce³⁺, and 0.200 M Cu²⁺, which metal hydroxides will precipitate first and last, respectively? K_sp for Ni(OH)₂ is 6.0x10^?16, for Ce (OH)₃ is 6.0 x 10^?22, and for Cu(OH)₂ is 4.8x10^?20.

A) Ni(OH)₂ first, Cu(OH)₂ last
B) Cu(OH)₂ first, Ni(OH)₂ last
C) Ni(OH)₂ first, Ce(OH)₃ last
D) Cu(OH)₂ first, Ce(OH)₃ last
E) Ce(OH)₃ first, Cu(OH)₂ last

Give detailed explanation

Please help me Calculate fraction denatured and equilibrium constant at each temperature and plot ln K vs T-1 graph, once plotted Find ΔH, ΔS and ΔG(T=75) (mention any assumptions you made) and What is the Tm for each protein

1. During a titration, it took 35.8mL of 0.10 M Be(OH)₂ to neutralize 65mL of HCl.

1. Write the balanced chemical reaction.
2. How many moles of beryllium hydroxide are needed to neutralize 2 moles of HCl?
3. What is the molarity of the HCl solution?

2. Consider a titration of 0.15M NaOH and 250 mL of 0.10M HBr.

1. What is the pH of the HBr solution before any base is added?
2. What is the pH after 50 mL NaOH is added?
3. What is the pH after 125 mL NaOH is added?
4. What is the pH after 150 mL NaOH is added?
5. Sketch the titration curve. Label the equivalence point on the graph and label the pH value at that point.

An engineer is designing a product in which a copper wire will carry large amounts of electricity. The resistive heating of a 66 g copper wire is expected to add 550 J of heat energy during a 10-minute operating cycle.

By what percentage does the volume increase because of the temperature increase?

(Note: Remember to always use unrounded values in calculations then round final answers to the correct significant figures.)

You may use the following information about copper to answer the question:

specific heat = 0.385 J g^-1 °C^-1

density = 8.94 g/cm³

coefficient thermal expansion = 6.5 µm m^-1 K^-1

Choose an organic compound to describe in depth; do not choose a nonmetal already selected

by another student. Include information on whether it is found in nature, how it can

be synthesized, its physical and chemical properties, and its uses or applications.