Matter and Properties
What type of mixture has the same composition throughout?
Homogeneous mixture
How many significant figures are in 0.00450?
3
Which scientist discovered the electron using the cathode-ray tube?
J. J. Thomson
Isotopes of an element have the same number of ______ but different numbers of ______.
Protons; neutrons
Which type of formula gives the simplest whole-number ratio of atoms?
Empirical formula
A liquid has a definite ______ but no definite ______.
Volume; shape
Calculate with correct significant figures: 12.11 + 0.3 + 1.045
13.5
Which scientist determined the charge of an electron using the oil-drop experiment?
Robert Millikan
A species has 17 protons and 18 electrons. What element and charge is it?
Cl⁻
What is the empirical formula of C₄H₈?
CH₂
Is density an intensive or extensive property?
Intensive
Calculate with correct significant figures: 4.20 × 3.1
13
What major conclusion came from Rutherford's gold-foil experiment?
Positive charge and most atomic mass are concentrated in a small nucleus / atom is mostly empty space
Element X has two isotopes: 10.0 amu at 75.0% and 11.0 amu at 25.0%. What is its average atomic mass?
10.25 amu
A bond between a metal and a nonmetal is usually what type of bond?
Ionic
Is water evaporating a physical or chemical change?
Physical change
Convert 1.25 × 10³ mg to grams.
1.25 g
Determine the protons, neutrons, and electrons in ⁵⁶₂₆Fe²⁺.
26 p, 30 n, 24 e
How many moles are in 40.08 g Ca? Molar mass = 40.08 g/mol.
1.000 mol Ca
What is the basic unit of H₂O? What is the basic unit of NaCl?
H₂O = molecule; NaCl = formula unit
A student gets 10.21 g, 10.22 g, and 10.21 g when the true value is 11.50 g. Are the measurements accurate, precise, both, or neither?
Precise but not accurate
A sample has a mass of 45.0 g and a volume of 18.0 mL. Calculate its density.
2.50 g/mL
During beta-minus emission, what happens to the mass number and atomic number?
Mass number stays the same; atomic number increases by 1
How many atoms are in 0.250 mol of an element?
1.51 × 10²³ atoms
Classify each: Ne, O₂, H₂O, NaCl as atomic element, molecular element, molecular compound, or ionic compound.
Ne = atomic element; O₂ = molecular element; H₂O = molecular compound; NaCl = ionic compound