1
A student notices that a metal sample is darker than another sample. This information was collected using the student's senses. What is this an example of?
Observation
A student measures the length of a desk using the standard SI unit for length. What unit should be used?
Meter
A student measures a sample as 49.9 g when the accepted value is 50.0 g. Which characteristic does this measurement demonstrate?
Accuracy
Two samples of the same substance have different masses but have the same density. Density is an example of what type of property?
Intensive Property
Sodium transfers an electron to chlorine. What type of bond forms between the resulting ions?
Ionic Bond
A student notices that a plant near a window grows taller and suggests that light may affect plant growth. What is this proposed explanation that can be tested?
Hypothesis
A scientist needs to measure the mass of a large sample using an SI base unit. What unit should be used?
Kilogram
A student measures the same object three times and gets 12.41 g, 12.42 g, and 12.40 g. Which characteristic do these measurements demonstrate?
Precision
A scientist doubles the amount of a substance and finds that its mass also doubles. Mass is what type of property?
Extensive Property
The slightly positive hydrogen of one water molecule is attracted to the slightly negative oxygen of another water molecule. What interaction is occurring?
Hydrogen Bond
A scientist changes the amount of fertilizer given to different plants while keeping everything else the same. What type of variable is the amount of fertilizer?
Manipulated/Independent Variable
A student reads a graduated cylinder incorrectly by looking at the top of the curved liquid surface instead of the bottom. What part of the measurement was read incorrectly?
Meniscus
A measurement is recorded as 25.40 g. How many significant figures should be included when reporting this measurement?
Four Significant Figures
Water freezes into ice. The substance remains H₂O before and after the change. What type of change occurred?
Physical Change
In a water molecule, oxygen attracts the shared electrons more strongly than hydrogen does. What type of bond connects the oxygen and hydrogen atoms?
Polar Covalent Bond
A scientist changes the temperature of water and records how long it takes sugar to dissolve. What type of variable is the dissolving time?
Responding/Dependent Variable
A sample has a mass of 60 g and a volume of 20 mL. What property can be determined using these two measurements?
Density
A student records the measurement 0.00450 g. Which zeros are not significant?
Placeholder Zeros
A piece of iron reacts with oxygen and produces rust with different properties from the original iron. What type of change occurred?
Chemical Change
An atom has 12 protons 13 neutrons and 10 electrons. What is the atomic number, mass number, and the charge
Atomic number = 12; Mass number = 25; Charge = +2
A student repeats an experiment several times and obtains very similar results each time. What concept does this demonstrate?
Reproducibility
A temperature of 25°C needs to be reported using the SI temperature scale. What unit should the student use?
Kelvin
A student records a measurement as 7000. g instead of 7000 g. What does the decimal point tell you about the zeros?
The trailing zeros are significant
An atom loses an electron and becomes positively charged. What is the resulting ion called?
Cation
Two atoms both contain 8 protons. One has 8 neutrons and the other has 10 neutrons. What are these atoms?
Isotopes