Unit 1 Nature of Science Chemistry

The safest technique for diluting a concentrated acid is to stir constantly while pouring the

• acid into the water slowly

• water into the acid slowly

• acid into the water quickly

• water into the acid quickly

A student reported that a wilted stalk of celery became crisp when placed in a container of ice water. The student then suggested that water entered the stalk and made it crisp. This suggestion is considered to be

• a control

• a hypothesis

• an observation

• a variable

Which sequence should be followed when conducting a laboratory investigation?

•  gather experimental data, make observations, form a conclusion, form a hypothesis 

  
  

• define a problem, form a hypothesis gather experimental data, form a conclusion

• form a hypothesis, form a conclusion, gather experimental data, define a problem

• make observations, gather experimental data, form a conclusion, state a problem 

  
  

A chemistry measurement shows .02760 grams of sodium chloride in a beaker. How many significant digits are in this measurement? 

• 5

• 4

• 3

• 2

Graphs of the data from laboratory investigations are used to

• observe general trends in the data

• make the observed data more accurate

• prevent errors in measuring data

• help change the original data tables

The results of one experiment carried out by a research team would be considered valid if

• the experiment had no control setup

• all the members of the research team came to the same conclusion 

• the experiment had more than one variable

• the experiment was repeated and the same results were obtained each time 

While a student is heating a liquid in a test tube, the mouth of the tube should always be 

• corked with a rubber stopper 

•  pointed toward the student

• allowed to cool 

• aimed away from everybody 

Elaine wants to measure the volume of a large pitcher of lemonade. Which units should Elaine use? 

• liters

• grams

• meters

• degrees

 Four students tried to  find out which magnet was the strongest. They each shared one idea. Which idea shows scientific thinking? 

• We can pick the longest magnet.

• We can pick the heaviest magnet.

• We can measure the strength of the magnets. 

• We can vote for the magnet that we think is the strongest. 

The diagrams at the left show five different tests Linda carried out using steel balls of three different sizes and masses. She used the same ramp for all trials. 

Linda wants to test this idea: if the ramp is placed higher, the ball will travel to the bottom of the ramp faster. Which three trials should Linda compare to test this idea?

• Trials 1, 2, and 3

• Trials 1, 3, and 5

• Trials 2, 3, and 4

• Trials 2, 4, and 5