How many moles of HCl must be added to 1.0 L of 1.0 M NH3(aq) to make a buffer with a pH of 9.00? (pKa of NH4+ =9.25)
the answer is 0.64, explain please.
In: Chemistry
When 20.0 mL of 1.0 M H3PO4 is added to 60.0 mL of 1.0 M NaOH at 25.0 degrees celcius in a calorimeter, the temperature of the aqueous solution increases to 35.0 degrees celcius.
Assuming that the specific heat of the solution is 4.18 J/(g⋅∘C), that its density is 1.00 g/mL, and that the calorimeter itself absorbs a negligible amount of heat, calculate ΔH in kilojoules/mol H3PO4 for the reaction.
H3PO4(aq)+3NaOH(aq)→3H2O(l)+Na3PO4(aq)
In: Chemistry
2. You are given three solutions to test in the lab: 1.0 M glucose, 1.0 M potassium nitrate, and 1.0 M potassium phosphate. Place the solutions in order from lowest to highest
a. boiling point
b. vapor pressure
c. freezing point
In: Chemistry
what is the ph of a 0.1M hydrochloric acid solution? A 1.0×10^-3M HCl solution? A 1.0 × 10^-8 M HCl solution?
In: Chemistry
A) A sealed container initially contains only 1.0 M gas A and 1.0 M gas B. Upon heating the following reaction takes place: A(g) + 2 B(g) ? C(g)+ 2 D(l). After the reaction comes to equilibrium, the concentration of gas C is 0.25 M. What is the equilibrium constant Kc for this reaction?
B). The decomposition of N2O4 into NO2 has Kp = 2. Some N2O4 is placed into an empty container, and the partial pressure of NO2 at equilibrium is measured to be 0.2 atm. What was the initial pressure in the container prior to decomposition?
C). For the following reaction, find the value of Q and predict the direction of change, given that a 1L flask initially contains 2 moles S8, 2 moles SF6, and 2 moles F2.
1/8 S8 (s) + 3 F2 (g) ? SF6 (g) Kc = 0.425
D)
A key step in the extraction of iron from its ore is
FeO(s) + CO(g) ? Fe(s) + CO2(g) Kp =0.403 at 1000°C.
What are the equilibrium partial pressures off carbon monoxide and carbon dioxide when 1.00 atm of carbon monoxide and excess iron(II) oxide react in a sealed container at 1000°C.
In: Other
What volumes of 1.0 M NH4NO3 and 1.0 M NH3 would be required to prepare 2.00 L of a buffer
with a pH of 9.00? The Kb of NH3 is 1.8 × 10–5.
How many grams of solid NaOH would need to be added to 5.00 L of 0.50 M acetic acid to
prepare a buffer with a pH of 5.00, assuming no volume change occurs upon the addition? The Ka of
acetic acid is 1.8 × 10–5.
In: Chemistry
If 100 mL of 1.0 M sulfuric acid, H2SO4, is neutralized with 1.0 M calcium hydroxide, Ca(OH)2, how many mL of base must be added?
In: Chemistry
A 1.0 kg ball and a 2.0 kg ball are connected by a 1.0-m-long rigid, massless rod. The rod is rotating cw about its center of mass at 19rpm .
What torque will bring the balls to a halt in 5.0s ?
Express your answer to two significant figures and include the appropriate units.
In: Physics
Compare the Greek arts to the Roman arts. When the Romans came to power, their art was heavily influenced by the Greeks, but with some changes. In what ways did the Romans change the Classics of the Greek artistic legacy? Include examples of how the Romans transformed Greek philosophy, architecture, theater, and sculpture and reinterpreted it into their own unique Roman style.
In: Psychology
Q1)According to economists, the biggest “cost” of unemployment is
a. increased “welfare” expenditures. c. the value of foregone output.
b. lost tax revenue. d. none of these.
Q2)
Which of the following statements is LEAST correct?
a. Inflation is a period of time during which the value of money is rising.
b. Affluent people – with assets other than money – can and often do benefit from inflation.
c. Both World War II (during the early 1940s) and the Vietnam War (during the late 1960s)
generated what’s known as demand-pull inflation.
d. “The Energy Crisis” of the 1970s generated what’s known as cost-push inflation.
Q3) The type of unemployment that economists find most concerning is
a. frictional unemployment. c. structural unemployment.
b. cyclical unemployment. d. voluntary unemployment.
In: Economics