ANSWERS GRADED A+
Limestone does NOT decompose when heated to 900 K because, at 900 K, ΔH is:
A.positive and less than TΔS.
B.positive and greater than TΔS.
C.negative and less than TΔS.
D.negative and greater than TΔS.
does not decompose = not spontaneous!!
therefore delta S needs to be - and delta H is +
B
,positive S means that it's going to be spontaneous
therefore we want S to be negative
When limestone is heated during Step 1, an equilibrium is established. Which of
the following expressions is the equilibrium constant for the decomposition of
limestone?
A.[CaO]
B.[CaCO3]
C.[CO2]
D.[CaO] × [CaCO3]
when writing Keq, NEVER include solids or liquids in the equation
only include aq or gas
Keq = [product]/[reactant]
During Reaction 2, did the oxidation state of N change?
A.Yes; it changed from -3 to -4.
B.Yes; it changed from 0 to +1.
C.No; it remained at -3.
,D.No; it remained at +1.
remember how to find the oxidation state!
hint, for the ion you're trying to find, have that has the X variable!
NH3
(x) + (3) = 0
x =-3
NH4+
x + (4) = +1
x = -3
If all of Gas X (from Step 6) is held in a sealed chamber at STP, what will be its
approximate volume?
A. 22.4 L
B. 44.8 L
C. 67.2 L
D. 89.6 L
1 mol = 22.4 L
, Why was it important that the cuvettes containing the glucose oxidase and the
blood sample were identical in terms of optical properties?
A. To enable the comparison of the absorption spectra
B. To reduce the absorption in the glass walls
C. To decrease the uncertainty in the wavelength
D. To increase the absorption in the solutions
Passage: "a blood sample with 1/30 dilution ratio was mixed in a transparent
cuvette with an oxygen-acceptor solution containing glucose oxidase."
curvettes in spectroscopy
they are measuring absorbance!! therefore we need to have a "reference" using the
curvette
A! to enable the comparison of the absorption spectra
What is the approximate energy of a photon in the absorbed radiation that yielded
the data in Table 1?
(Note: Use 1 eV = 1.6 × 10–19 J and hc = 19.8 × 10–26 J•m.)
A. 1 eV