Lab Safety
What are key lab safety procedures
Wearing protective equipment, dispose chemicals properly, keep a clean woke area
What property of matter describes its resistance to flow
Viscosity
How do you solve percentage error
The absolute value of the difference of the measured value and the actual value divided by the actual value and multiplied by 100
What type of matter is a food product label
PET film, vinyl, polypropylene, acrylic
What tools are used to measure mass
Balances, scales, and mass spectrometer
What should you do before starting any experiment
Clean the work area, tie hair up, wear goggles
How does the density of a substance relate to its buoyancy in a liquid
The density of a substance determines its buoyancy in a liquid. If the density of the substance is greater than that of liquid, it will sink. Conversely, if the density of the substance is less than that of liquid it will float
How do you calculate the percent error
Percent error= (Estimated number-Actual number)/Actual number)x100
What other substances, in addition to water, can exist naturally on earth in at least three states of matter
Mercury and water
What unites are used to measure mass
Grams and kilograms
What should you do if you spill a chemical on your skin in the lab
Immediately rinse the affected area with water for at least 15 minutes and notify your instructor or supervisor
How does the density of a substance change with temperature
Generally, as temperature increase, the density of a substance decreases because the molecules move faster and occupy a larger volume resulting in decreased density. Conversely as temperature decreases the density of a substance increases as molecules move slower and occur a small we volume, leading to increased density
A student measures the density of a substance in a lab experiment and obtains a value of 8.5 g/mL. The accepted value for the density of the substance is 9.0 g/mL. Calculate the percent error of the percent measurement
Percent error=5.56%
What substance can exist naturally in two different states
Liquid and solid
The amount of space occupied by any three- dimensional solid
Why is it important to properly label chemical containers in a laboratory
It reduces the risk of accidents or mishaps
What changes do heating and cooling cause?
Chemical changes in which atoms alter their bonding to form a new substance
Explain how to calculate percent error in an experiment, and why it’s important to consider in scientific analysis
Percent error is calculated by taking the absolute value of the difference between the experimental value and the accepted value, dividing it by the accepted value and Then multiplying by 100. It’s important in scientific analysis Because it helps assess the accuracy of experimental results by quantifying the deviation from the true or accepted value. This allows researches to identify and correct sources of error.
What properties can be used to identify matter?
density, colour, mass, volume, length, etc
What tools are used to measure volume
Beakers, burettes, pipettes, etc
Describe the hierarchy of controls in laboratory safety and provide an example of each
Describe the hierarchy of controls in laboratory safety consists of elimination, substitution, engineering and personal protective equipment
How can materials be alike and different
All materials are made up of atoms or combination of same or different atoms
A student conducts an experiment to measure the density of a substance and obtains a value of 8.5g/cm^3. The accepted value from a reliable source is 8.0g/cm^3
Percent error= 0.5/8.0x100%=6.25%
Liquids Are easy to compress (T OR F)?
True
What units are used to measure volume
Liters, milliters,and cubic meters(m^3)