Chapter 11 - Uncertainty and Measurement Review

Which value of q, in J, has the correct number of significant figures? q = mcΔT where m = 2.500 g, c = 4.18 J/gK and ΔT = 0.60 K

• 6

• 6.3

• 6.27

• 6.270

What is the index of hydrogen deficiency, IHD, of 3-methylcyclohexene

• 0

• 1

• 2

• 3

What is the ratio of the areas of the signals in ¹H NMR spectrum of pentan-3-ol

• 6:4:1:1

• 6:2:2:2

• 5:5:1:1

• 3:3:2:2:1:1

Which feature of a molecule does infrared spectroscopy detect?

• molecular mass

• bonds present

• total number of protons

• total number of proton environments

How are the uncertainties of two quantities combined when the quantities are multiplied together?

• Uncertainties are added

• Percent uncertainties are multiplied

• Uncertainties are multiplied

• Percent uncertainties are added

The rate of a reaction is studied at different temperatures. What is the best way to plot the data?

• X-axis is rate, the dependent variable

• X-axis is rate, the independent variable

• X-axis is temperature, the dependent variable

• X-axis is temperature, the independent variable

A student performs an acid-base titration using a pH meter, but forgets to calibrate it. Which type of error will occur and how will it affect the quality of the measurements?

• Random error and lowers precision

• Systematic error and lowers accuracy

• Systematic error and lowers precision

• Random error and lowers accuracy

What information is provided by ¹H NMR, MS, and IR for a compound?

I. ¹H NMR: chemical environments for protons

II. MS: fragmentation pattern

III. IR: types of functional groups

• I and II only

• I and III only

• II and III only

• I, II, and III

Which compound gives this ¹H NMR spectrum?

• CH₃CH₂OCH₂CH₃

• CH₃CH₂OH

• CH₃CH₂CH₃

• CH₃CH₂CH₂OH

Which technique is used to determine the bond lengths and bond angles of a molecule?

• X-ray crystallography

• Infrared(IR) spectroscopy

• Mass spectroscopy

• ¹H NMR spectroscopy