Evolution & Genetics
What type of natural selection favors individuals with average traits, reducing extremes in a population?
What is stabilizing selection?
What law must be followed when balancing chemical equations?
What is the Law of Conservation of Mass?
What part of the atom contains protons and neutrons?
What is the nucleus?
What device is used to measure heat transfer in a reaction?
What is a calorimeter?
What is the sum of pH and pOH in a solution?
What is 14?
What process copies a gene's DNA sequence to produce a complementary strand of mRNA?
What is transcription?
What type of chemical reaction breaks down a single compound into two or more simpler substances?
What is a decomposition reaction?
What are the electrons in the outermost shell called?
What are valence electrons?
What does a positive ΔH mean in a reaction?
What is the reaction is endothermic?
What type of solution has a low concentration of [OH-]?
What is an acidic solution?
What does a Punnett square help predict?
What are possible offspring genotypes?
A reaction requires 1 molecule of A to react with 2 molecules of B. If you mix 4 molecules of A with 6 molecules of B, which reactant will be left over after the reaction?
Reactant A
What bond involves the equal sharing of electrons?
What is a nonpolar covalent bond?
When molten iron solidifies into a solid metal, what happens to the entropy of the system?
What is entropy decreases?
A solution has a hydroxide ion concentration [OH−] of 2.5×10−5. Calculate the pH.
What is 9.40?
What term describes the permanent change in the DNA sequence of a gene?
What is mutation?
Balance: C3H8+O2→CO2+H2O
C3H8+5O2→3CO2+4H2O
An element has an atomic number of 17 and a mass number of 35. How many neutrons does it have?
What is 18?
A 10.0-gram sample of oxygen gas (O₂) is contained in a 5.00 L container at 300 K. What is the pressure inside the container?
(Use R = 0.0821 L·atm/mol·K, molar mass O₂ = 32.00 g/mol)
1.54 atm pressure inside the container
Two compounds, Compound X and Compound Y, have similar molecular weights and both contain oxygen atoms. Compound X boils at 110°C, while Compound Y boils at 60°C. Without knowing their exact structures, explain why Compound X has a much higher boiling point.
What is Compound X can form hydrogen bonds due to having O–H groups
In a dihybrid cross (AaBb × AaBb), what is the probability of an offspring being homozygous recessive for both traits?
What is 1/16?
DAILY DOUBLE
Given the reaction:
2Al+3Cl2→2AlCl3
How many grams of aluminum chloride (AlCl₃) are produced when 5.4 grams of aluminum react completely with chlorine gas?
(Molar masses: Al = 26.98 g/mol, Cl₂ = 70.90 g/mol, AlCl₃ = 133.34 g/mol)
26.67 grams of aluminum chloride produced
Why is the atomic mass of an element usually a decimal rather than a whole number?
Because it represents the weighted average of the masses of all naturally occurring isotopes of that element.
DAILY DOUBLE
Given the reaction:
2SO2+O2→2SO3
And these standard enthalpies of formation (ΔH°f):
ΔH°rxn = –198 kJ (overall reaction enthalpy)
ΔH°f (SO₂) = –297 kJ/mol
ΔH°f (O₂) = 0 kJ/mol (element in standard state)
Calculate the standard enthalpy of formation (ΔH°f) for SO₃
-396 kJ/mol
How many liters of a 0.500 M NaCl solution can be made from 25.0 grams of NaCl? (Molar mass of NaCl = 58.44 g/mol)
0.856 liters