CHM 161 7-8
A 26.1 mL sample of H2 gas was collected from an experiment at 1.025 atm and 21.4 °C. How many moles of gas are in this sample?
1.11*10^-3
What factors might impact how well a compound dissolves into water? Select one or more: A: The particle size of the solute B: Temperature of the solution C: The color of the solute D: The type of container holding the solution E: Stirring as the solute dissolves
A: The particle size of the solute B: Temperature of the solution E: Stirring as the solute dissolves
When drawing the Lewis structure of the H2CO molecule, the structure should represent a total of ____ valence electrons. Based on the elements present, a total of ____ electrons are needed for a stable structure. Thus, there should be ____ bonds in the structure. The ________ atom should be in the center with ____________________ and _______________________.
12, 20, 4, C, single bonds to each H atom, a double bond to the O atom
Determine the bond angle for each given molecule around the central atom. BH3 CO2 SiH4 H2O
120, 180, 109.5, 104.5
The temperature of a room is 24.3 °C. What is this temperature expressed in Kelvin (K)?
297.3 K
The reading on a barometer is 29.1 inHg. What is this value in mmHg?
739 mmHg
A sample of gas is subject to changes in conditions. Predict the effect of each change. The volume and temperature remain constant, while some of the gas is let out of the container. What will happen to the pressure? The pressure and volume are increased. What will happen to the temperature? The pressure is kept constant, while the temperature is decreased. What will happen to the volume? The pressure and the temperature are both decreased by 50%. What will happen to the volume?
It will decrease, it will increase, it will decrease, it will stay the same
If a barometer reading gives a pressure of 746 mmHg, what is the pressure in atm? What is the pressure reading from the barometer in torr?
0.982 atm, 746 torr
Determine the molecular geometry based on the description of bonding and lone pairs of electrons around the central atom. Four single bonds and no lone pairs of electrons Five single bonds and no lone pairs of electrons Six single bonds and no lone pairs of electrons Two double bonds and no lone pairs of electrons Two single bonds and two lone pairs of electrons Three double bonds and no lone pairs of electrons Three single bonds and one lone pair of electrons
tetrahedral, trigonal bipyramidal, octahedral, linear, bent, trigonal planar, trigonal pyramidal
To measure out a volume of liquid, start by choosing the appropriate graduated cylinder and moving the bumper to the _______________ of the graduated cylinder to protect it from breakage. Then, pour the liquid into the graduated cylinder until the _____________________ of the meniscus aligns with the desired volume marking when you look at the graduated cylinder from ________________________.
top, bottom, eye level
Determine the strongest intermolecular force present between the molecules in a bulk sample of the described molecules. Molecules with no permanent dipole moment Molecules with a permanent dipole moment such as an−OH−OH group Molecules with a permanent dipole moment such as a C=O group
dispersion forces, hydrogen bonding, dipole-dipole forces
Arrangement of bonding and non-bonding electron domains is ________________________. Arrangement of only the atoms in a molecule is ___________________________.
electron geometry, molecular geometry
Consider the structures of CCl4 and NH3. The bond angles in CCl4 should be __________________ than the bond angles in NH3. The lone pair of electrons on the _____________ atom changes the bond angles from the ideal value because a lone pair of electrons take up ___________________ the electrons in a bond.
greater than, nitrogen atom, more space than
Match each description to the correct term. a liquid consisting of one substance dissolved in another a liquid that dissolves another substance a chemical that is dissolved a value used to describe the amount of one substance dissolved in another
solution, solvent, solute, concentration
When drawing the Lewis structure of the HCN molecule, the structure should represent a total of ___ valence electrons. A ___ atom should be in the center with _______________________ and ___________________________.
10, C, a single bond to the H atom, a triple bond to the N atom
A pressure of 705 torr is equal to what value in atmospheres (atm)?
0.928 atm
Most laboratory chemical spills are cleaned up in a similar manner, but acid and base spills require an extra step. What is this extra step? Select one: A: Alert the proper authorities about the corrosive chemical waste. B: Be sure to replace the spilled acid or base. C: Tell all other lab participants to evacuate the lab as quickly as possible. D: Neutralize the spill before cleaning it up.
D: Neutralize the spill before cleaning it up.
It is often helpful to remember the acronym PASS when using a fire extinguisher. Fill in the word that corresponds with each letter to complete the steps needed for operation of this device. ___________ the pin ___________ the nozzle at the base of the fire ___________ the lever slowly ___________ the spray from side to side over the fire.
Pull, Aim, Squeeze, Sweep
When two miscible fluids are mixed, they form layers/a precipitate/a solution at fixed masses/only high temperatures/any ratio of the component fluids.
a solution, any ratio
Identify tools that are ideal for cleaning glassware. Select one or more: A: Brushes B: Reusable cloths C: Detergent and water D: Steel wool
A: Brushes C: Detergent and water
When using vacuum filtration to separate two solids, what techniques should you use to ensure a quantitative separation? Select one or more: A: Carefully rinse the flask into the filter funnel with a small amount of water. B: Dry the solid on the filter paper after the separation. C: Wet the filter paper before pouring the mixture into the filter funnel. D: Wash the solid on the filter paper with a small amount of water.
A: Carefully rinse the flask into the filter funnel with a small amount of water. B: Dry the solid on the filter paper after the separation. C: Wet the filter paper before pouring the mixture into the filter funnel. D: Wash the solid on the filter paper with a small amount of water.
Which elements do not strictly follow the octet rule when they appear in the Lewis structure of a molecule? Select one or more: A: Chlorine B: Carbon C: Hydrogen D: Sulfur E: Fluorine F: Oxygen
A: Chlorine C: Hydrogen D: Sulfur
Which types of signs are posted to convey information about chemical storage? Select one or more: A: Hazard signs such as "Flammable," "Oxidizer," and "Corrosive" B: National Fire Protection Association (NFPA) diamond C: Gas Cylinder sign D: Exit sign E: Safety equipment signs such as "Safety Shower" and "Eyewash Station"
A: Hazard signs such as "Flammable," "Oxidizer," and "Corrosive" B: National Fire Protection Association (NFPA) diamond C: Gas Cylinder sign
Identify the true statements concerning vapor pressure. Select one or more: A: Vapor pressure depends on the temperature of a substance. B: Vapor pressure does not depend on the intermolecular forces between molecules. C: Vapor pressure is lower for a substance that involves hydrogen bonding. D: Vapor pressure is the pressure of evaporated gas above a liquid or solid.
A: Vapor pressure depends on the temperature of a substance. C: Vapor pressure is lower for a substance that involves hydrogen bonding. D: Vapor pressure is the pressure of evaporated gas above a liquid or solid.
What is the definition of solubility? Select one: A: A homogeneous mixture of a compound dissolved into a fluid B: The fluid into which a compound dissolves C: The extent to which a compound dissolves into a specified fluid D: The compound that dissolves into a fluid
C: The extent to which a compound dissolves into a specified fluid
Identify the expected color of each element in a model of a molecule. Carbon Oxygen Nitrogen Hydrogen
black, red, blue, white
When drawing the Lewis structure of a molecule, start by determining the total number of available valence based on each element's total ionic charge/group number/atomic number. Then, use the total number of electrons needed for each element to be stable, generally based on the octet rule/its charge/VSEPR theory, to determine the steric number/ionic charge/total number of bonds by finding the difference between the number of needed and available electrons divided by two. Next, identify the central atom, which is the element with the greatest electronegativity/fewest valence electrons/most negative charge other than hydrogen. Finally, arrange the number of bonds around the central atom to fulfill the stable number of electrons for each element.
group number, the octet rule, total number of bonds, fewest valence electrons
Hydrogen bonding is a type of intermolecular force/covalent bond/ionic bond that exists within/between molecules or parts of molecules that contain a hydrogen bonded to a O, F, or Cl/N, O, or F/C, N, or O/F, Cl, or Br atom. Hydrogen bonding is so strong because the hydrogen has a significant partial ionic/negative/positive charge due to the other atom's high covalent character/atomic number/electronegativity.
intermolecular force; between; N, O, F, ; positive; electronegativity
Identify the molecular geometry corresponding to each expected bond angle around the central atom. 180 109.5 107 120
linear, tetrahedral, trigonal pyramidal, trigonal planar
Consider the equation M1V1=M2V2M1V1=M2V2 where M represents molarity and V represents volume for two solutions, 1 and 2. You can use the equation for calculations involving the reaction of two solutions/only for calculations involving dilution of solutions/for any calculations involving two solutions/only for calculations involving aqueous solutions because the equation requires that the solvent is the same for the two solutions/the equation is true for any two solutions that react together/the equation requires that moles of solute are equal between the two solutions/all solutions can be described in terms of molarity and volume.
only for calculations involving dilution of solutions, the equation requires that moles of solute are equal between the two solutions
A hydrocarbon is saturated if only pure compounds/only single bonds/any solvents/any multiple bonds are present. Alkynes/Aromatics/Aqueous solutions/Alkanes are saturated hydrocarbons. A hydrocarbon is unsaturated if any multiple bonds/only single bonds/only pure compounds/any solvents are present. Solid organics/Organic solutions/Alkanes/Alkenes are unsaturated hydrocarbons.
only single bonds, alkanes, any multiple bonds, alkenes
