Semester 1 Exam 2024-2025 A

Front

Why wear safety goggles in a chemistry experiment?

Back

To protect your eyes from harmful substances

Answer explanation

The primary purpose of wearing safety goggles is to protect your eyes from harmful substances, especially during experiments where spills can occur. This ensures safety and prevents potential injuries.

Front

What should Ava NOT do when handling chemicals?

Back

Taste a small amount to identify it.

Answer explanation

Ava should NOT taste a small amount to identify a chemical, as this can be extremely dangerous. Proper safety measures include reading labels, wearing gloves, and using a fume hood.

Front

What is the primary use of a beaker?

Back

Holding and mixing liquids

Answer explanation

The primary use of a beaker in Ava's experiment is for holding and mixing liquids. While beakers can be used for other purposes, their main function is to contain and combine substances during experiments.

Front

If a fire breaks out in the lab, what should be done first?

Back

Alert the teacher or supervisor

Answer explanation

In case of a fire, the first step is to alert the teacher or supervisor. They are trained to handle emergencies and can take appropriate action, ensuring everyone's safety.

Front

Which lab equipment should Lily use to transfer small amounts of liquid accurately?

Back

Pipette

Answer explanation

Lily should use a pipette for transferring small amounts of liquid accurately, as it is specifically designed for precise liquid measurement, unlike a test tube, Bunsen burner, or thermometer.

Front

How many millimeters is 2.5 meters?

Back

2,500 mm

Answer explanation

To convert meters to millimeters, multiply by 1,000. Thus, 2.5 meters x 1,000 = 2,500 mm. Therefore, the correct answer is 2,500 mm.

Front

What is 0°C in another temperature scale?

Back

273.15 K

Answer explanation

0°C is equivalent to 273.15 K in the Kelvin scale, as the Kelvin scale starts at absolute zero, which is -273.15°C. Therefore, the correct answer is 273.15 K.

Front

How many kilograms are in 4,500 grams?

Back

4.5 kg

Answer explanation

To convert grams to kilograms, divide by 1,000. Thus, 4,500 grams ÷ 1,000 = 4.5 kg. Therefore, Mason needs 4.5 kg of flour.

Front

Convert 50°C to Kelvin.

Back

323.15 K

Answer explanation

To convert Celsius to Kelvin, use the formula K = °C + 273.15. Thus, 50°C + 273.15 = 323.15 K. Therefore, the correct answer is 323.15 K.

Front

Which measurement is closest to 1 liter? 10 dL, 1,000 cm³

Back

10 dL

Answer explanation

1 liter is equivalent to 10 deciliters (dL). Therefore, 10 dL is the closest measurement to 1 liter, while the other options (100 mL, 10,000 cL, and 1,000 cm³) do not equal 1 liter.