In: Chemistry
The enthalpy change under standard conditions for which of the reactions below would be equal to the ∆H°f of NaOH(s)? (A) Na(s) + H2O(l) NaOH(s) + 1/2 H2(g) (B) Na(s) + 1/2 O2(g) + 1/2 H2(g) NaOH(s) (C) Na(s) + 1/2 H2O2(l) NaOH(s) (D) Na+(aq) + OH–(aq) NaOH(s) please explain why you chose that answer and why the other answers are wrong. If it has to do with them being in their standard states, how do I know what the standard states of the elements are.
In: Chemistry
When light of wavelength equal to 364 nm strikes a metal, the kinetic energy of the ejected electron is 4.12 × 10-19 J. What is the work function of the metal?
In: Chemistry
The reaction
Zn(NO3)2 + 4NaOH ---> Zn(OH)42- + 2NO-3 + 4Na+
If 25 mL of a 0.10 M Zn(NO3)2 is added to 10.0 mL of 0.65 M NaOH and at equilibrium the concentration of Zn(OH)42- is found to be 0.012 M, find Kc
In: Chemistry
Elemental S reacts with O2 to form SO3 according to the reaction
2S+3O2→2SO3
A) How many O2 molecules are needed to react with 4.13 g of S?
Express your answer numerically in units of molecules.
B) What is the theoretical yield of SO3 produced by the quantities described in Part A?
Express your answer numerically in grams.
C) Next, consider a situation in which all of the S is consumed before all of the O2 reacts, or one in which you have excess S because all of the O2 has been used up.
For each of the given situations, indicate whether S or O2 is the limiting reactant.
- 3.00 mol Sulfur, 3.00 mol Oxygen
-3.00 mol Sulfur, 4.00 mol Oxygen
-3.00 mol Sulfur, 5.00 mol Oxygen
In: Chemistry
I compress an ideal gas under a constant pressure of 3.2 × 105 Pa from 6.31 mL to 5.12 mL.
i. What is the work done in this process?
ii. If this is an adiabatic process, what is q and ∆U for this process?
In: Chemistry
You have the following solutions at your disposal to prepare a buffer solution with a pH greater than 7.0:
(1) 50.0 mL of 0.35 M NH3 Kb = 1.8×10-5 (2) 55.0 mL of 0.35 M NaOH
(3) 50.0 mL of 0.35 M HCl (4) 16.5 mL of 0.35 M NaCl NaOH
(5) 16.5 mL of 0.35 M HNO3 (6) 16.5 mL of 0.35 M KOH
(a) Assuming that you are going to mix the entire quantity of the listed solutions to prepare the buffer, which two solutions would you use?
In: Chemistry
Given the provided enthalpies of formation, calculate ΔH for the reaction shown.
2 H2 (g) + O2 (g) → 2 H2O (g) ΔH = -483.6 kJ
3 O2 (g) → 2 O3 (g) ΔH = +285.4 kJ
6 H2 (g) + 2 O3 (g) → 6 H2O (g) ΔH = ?
In: Chemistry
When 25.00 mL of unknown were passed through a Jones reductor, molybdate ion (MoO42-) was converted into Mo3+. The filtrate required 16.43 mL of 0.01033 M KMnO4 to reach the purple end point.
MnO4- + Mo3+ → Mn2+ + MoO22+
A blank required 0.01 mL. Balance the reaction. (Use the lowest possible coefficients. Omit states-of-matter.)
Find the molarity of molybdate in the unknown.
In: Chemistry
A beaker with 125 mL of an acetic acid buffer with a pH of 5.000 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 7.00 mL of a 0.360 M HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.740.
In: Chemistry
iron nail and copper (II) sulfate the compound contains Fe2+
molecular equation
ionic equation
net ionic equation
spectator ions
In: Chemistry
3Mg +2AlCl3 -------> 2Al +3MgCl2
a)calculate the mass of aluminium chloride that will react with 40g
of magnesium.
b) calculate the mass of each product formed from the reaction of 40g of mg
2)when propane gas C3H8 is burned with oxygen 50g of water is collected.what mass of propane was burned?
3)metallic iron can be produced by reacting iron(iii) oxide with carbon as shown below.when 100g of iron(iii)oxide is reacted, 45g of iron metal is obtained.what is the percent yield of the reaction?
In: Chemistry
current event or recent research related to atoms,atomic structure or chemical bonds.
In: Chemistry
1. A soil has the following cations reported as cmolc per kg of soil Ca = 6; Mg = 4; K = 3; Na = 2; Al3+ = 10.
a. Calculate the CEC of the soil (cmolc per kg) ( 1 point)
b. Calculate the base saturation (2 points)
c. How much CaCO3 needs to be added to this soil to raise the base saturation to 80%? (3 points)
d. How much CaO needs to be added to this soil to raise the base saturation to 80%? (4 points)
In: Chemistry