Lab tools, hazard symbols and Safety Data Sheets

Answer Key - Grade 10 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   Safety rule: measure at most 25 mL of 6 M acid at a time. What is the largest volume of 0.5 M acid that can be made, in mL, Ari?

   300 mL
2. 2.

   Safety rule: measure at most 50 mL of 2 M acid at a time. What is the largest volume of 0.1 M acid that can be made, in mL, Esme?

   1000 mL

3. Read this first

   Table

   Three SDS excerpts (made-up products), 3 rows. Columns: chemical | Section 2 hazard | Section 7 storage | Section 10 incompatible with. Row 1: Cleaner T | Danger. Oxidizer. Causes serious eye damage. | Store cool, away from fuels and combustible materials. | Flammable liquids and strong acids.. Row 2: Solvent S | Danger. Highly flammable liquid and vapor. | Store in a flammables cabinet, away from heat and sparks. | Oxidizers.. Row 3: Acid A | Danger. Strong acid. Causes severe skin burns and eye damage. | Store in a corrosives cabinet, away from bases. | Bases and metals..

4. 3.

   The stockroom has a flammables cabinet, a corrosives cabinet and an open shelf. Where should Cleaner T go, Jun?

   • In the corrosives cabinet, since its Section 2 lists eye damage and Acid A is kept there
   • On the open shelf, apart from the other two, since Section 10 lists flammables and acids
   • In the flammables cabinet, since Danger products are stored together in one place
5. 4.

   Solvent S and Acid A: may they share the corrosives cabinet, Kira?

   • No: Section 7 sends Solvent S to a flammables cabinet, though Acid A's Section 10 omits flammables
   • Yes: neither Section 10 lists the other chemical, so no rule forbids them sharing a cabinet
   • Yes: both are Danger products, and the corrosives cabinet is the sturdier of the two cabinets
6. 5.

   Cleaner T spills beside Solvent S bottles. Which entries together justify moving S away at once, Luz?

   • Cleaner T's Section 7 (store cool) with its Section 2 eye-damage warning for anyone nearby
   • Solvent S's Section 2 (flammable) with Acid A's Section 7 (away from bases), both Danger
   • Cleaner T's Section 2 (oxidizer) and Solvent S's Section 10 (oxidizers), plus S's Section 7

7. Glycerin trial (example data)

   measurement	reading
   cylinder and glycerin (g)	55.20
   empty cylinder (g)	23.70
   volume (mL)	25.0
   student's density (g/mL)	2.21
   accepted density (g/mL)	1.26

8. 6.

   The student's density is far above the accepted value. Which error explains it, Milo?

   • The meniscus was read at the top edge, a slip of well under 1 mL
   • The empty cylinder was not subtracted: 55.20 ÷ 25.0 gives exactly 2.21
   • A bubble in the liquid made the volume read too large, which raises the density
9. 7.

   A wet cylinder leaves about 1.0 mL of water when Noah measures 20.0 mL of 6.0 M acid, then dilutes to 250 mL. The target was 0.48 M. What results?

   • Exactly 0.48 M, since the final volume is still 250 mL
   • About 0.50 M, a little above 0.48 M, since the wet glass adds volume
   • About 0.46 M, a little below 0.48 M, since only about 19 mL was acid

10. Four density trials of one stone (example data)

    trial	rise (mL)	density (g/mL)
    1	10.0	2.67
    2	10.1	2.64
    3	10.0	2.67
    4	11.1	2.41

11. 8.

    Each trial used the same 26.70 g stone. Which error explains trial 4, Pia?

    • A bubble on the stone added about 1 mL to the rise, so the density fell
    • The stone was weighed wet, which would lower the density as trial 4 shows
    • The empty dish was not subtracted, which would lower the density as trial 4 shows

12. Accepted densities (rounded)

    material	density (g/mL)
    aluminum	2.70
    quartz	2.65
    zinc	7.14
    tin	7.29
    iron	7.87
    magnesium	1.74

13. 9.

    A stone measures 2.67 ± 0.04 g/mL. Does the measurement identify it, Ren?

    • No: the range 2.63 to 2.71 includes both quartz at 2.65 and aluminum at 2.70
    • Yes, aluminum: 2.70 is the lone metal in the table near 2.7, so it is the match
    • Yes, quartz: 2.65 is the closest accepted value to 2.67, so it is the likely match
14. 10.

    Student A reports 2.69 ± 0.06 g/mL and student B reports 2.71 ± 0.01 g/mL for aluminum. Which statement is supported, Zee?

    • Both agree with aluminum, but only B's range also excludes quartz at 2.65
    • A alone agrees with aluminum, since 2.69 is closer to 2.70 than B's value
    • B is less reliable, since 2.71 is farther from aluminum's 2.70 than 2.69 is