Formulas and Calculations Flashcards

An animal room is maintained at 68°F. What is this temperature in Celsius?

Answer: 20°C

The formula is °C = (°F − 32) × 5/9. So (68 − 32) × 5/9 = 36 × 5/9 = 20°C. The recommended temperature range for most laboratory rodents is 18–26°C (64–79°F).

You need to make 100 mL of a 1:10 dilution of a disinfectant in water. How many mL of disinfectant do you use?

Answer: 10 mL

A 1:10 dilution means 1 part concentrate per 10 parts total solution. For 100 mL total: 100 ÷ 10 = 10 mL of disinfectant, then add 90 mL of water to reach 100 mL.

A mouse weighs 25 grams and requires a drug at 10 mg/kg. What dose in mg should the mouse receive?

Answer: 0.25 mg

First convert grams to kilograms: 25 g = 0.025 kg. Then: 0.025 kg × 10 mg/kg = 0.25 mg. Accurate weight-based dosing is critical for both animal welfare and experimental validity.

You need 1 liter of a 2% disinfectant solution. Your stock is 20% concentration. How many mL of stock do you need?

Answer: 100 mL

Using the dilution formula C1V1 = C2V2: (20%) × V1 = (2%) × 1000 mL, so V1 = 2000 / 20 = 100 mL of stock. Add water to bring the total volume to 1000 mL.

A room thermometer reads 30°C. The acceptable range for the species housed is 64–79°F. Is this within range?

Answer: No — 30°C equals 86°F, which is too warm

Converting: °F = (30 × 9/5) + 32 = 54 + 32 = 86°F. Since 86°F exceeds the upper limit of 79°F, the temperature is out of range and must be reported immediately as an abnormal environmental parameter.

A rat weighs 300 g. Its blood volume is approximately 6% of body weight. IACUC policy limits a single blood draw to 10% of total blood volume. What is the maximum volume that may be drawn?

Answer: 1.8 mL

Total blood volume = 300 g × 6% = 18 mL. Maximum single draw = 18 mL × 10% = 1.8 mL. This two-step calculation protects the animal by preventing excessive blood loss.