Chemistry Exam 1 (What)

What mass of He contains the same number of atoms as 5.0 g Kr?

0.24g

What is the correct method for calculating the number of atoms in 1.0x 10^-5 mole Al?

1.0 x 10^-5 mole Al(6.02x 10^23 atoms Al/1 mole Al)

What is the energy of a single photon with a wavelength of 663 mm?

3.14 x 10^-19 J

What is the correct answer to the following expression: 3.33 x 10^-5 + 8.13 x10^-7?

3.41 x 10^-5

What is the mass of 0.229 mol Mg?

5.57g

What is the correct answer to the following expression: (27+93) x 5.1558?

619

What is the correct answer to the following expression: (49.1-42.61)x 13.1?

85

What is the difference between accuracy of measurements and the precision of measurements?

Accuracy is an indicator of how close a measurement, or the average of a set of measurements, is to the correct value. Precision is an indicator of how close two measurements are to each other, or how much numerical spread is present in a set of measurements.

What is the name of the element with the symbol B

Boron

What are the names of the four metalloids?

Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium

What alkaline earth metal is in the fourth period?

Ca

What halogen is in the second period?

F

What is the correct symbol for iron?

Fe

What's the correct symbol for potassium?

K

What is the name of the element with the symbol Pb

Lead

What method is used to determine the exact masses of isotopes and their relative abundances?

Mass spectrometry

What element is in the third period in group 5A?

P

What is a correct method for converting Celsius to Kelvin

t(K) =1K/ 1C(tC+273.15C)