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Electronic single-pan balances with digital readouts are now favoured over mechanical types and are common in most laboratories. There are essentially two types of balance:
General-purpose balances which weigh to the nearest 0.01 g with a capacity of about 300 g. Chemicals may be dispensed for weighing, into a suitable weighing container, directly onto these balances.
Analytical four-figure balances for quantitative work, which weigh to the nearest 0.0001 g (0.1 mg) and have a maximum capacity of about 100 g. Chemicals must not be transferred onto the balance at any time and analytical balances must only be used for weighing by difference.
Both types are illustrated in Fig. 4.3 and you should familiarize yourself with their operation before use.
What else can I help you with?
Why should the bulb of the thermometer not touch the sides and bottom of the container when the temperature of the substance in it is to be taken?
The container may not be the same temperature as the solution (especially if the container is not a very good heat conductor). Thus, having the bulb of the thermometer touch the container may give an inaccurate reading.
Why should a piece of laboratory tissue or tongs be used to handle a sample container to be weighed?
Using laboratory tissue or tongs to handle a sample container when weighing it helps to prevent contamination of the sample. Any oils, dirt, or residues on your hands could transfer to the container and affect the accuracy of the measurement. Additionally, using these tools helps ensure the sample remains untouched by any external substances.
How long does contact adhesive take to dry?
Contact adhesive typically takes about 15-30 minutes to dry, but it is best to follow the manufacturer's instructions for specific drying times. The adhesive should be allowed to fully dry before applying pressure or using the bonded surfaces.
Which substance should you choose based on having the highest boiling point?
The substance with the highest boiling point is the one you should choose.
What does the mark on the container mean?
The mark on the container typically indicates information such as the material, capacity, manufacturer, and sometimes recycling information. It is there to help users identify important details about the container and how it should be used or recycled.
Why should the bulb of the thermometer not touch the sides and bottom of the container when the temperature of the substance in it is to be taken?
The container may not be the same temperature as the solution (especially if the container is not a very good heat conductor). Thus, having the bulb of the thermometer touch the container may give an inaccurate reading.
What is the mass of a 25 ml graduated cylinder?
If a solid that has a mass of 25 grams melts, it should result in a _______ with a mass of _______ grams.
What is the correct weighing procedure when using the class A balance?
The substance should be placed on the left pan and the weights should be placed on the right pan and the balance must be arrested (Locked) so as to prevent any unnecessary movement.
What type of adhesive should be used for bonding materials to polystyrene, and what are the characteristics of a polystyrene compatible adhesive?
A solvent-based adhesive is recommended for bonding materials to polystyrene. A polystyrene compatible adhesive should have low viscosity, good wetting ability, and should not contain solvents that can dissolve or damage the polystyrene surface.
When labeling a non blood specimen why is it important to place the label on the container itself and not the lid?
This is likely to ensure that, should the lid be removed or misplaced, the substance is still identifiable.
What properties would the substance have so that it could be used to surround a container that would keep food hot?
The substance used to surround a container for keeping food hot should have high thermal insulation properties to minimize heat loss, such as low thermal conductivity. It should also be lightweight and durable to ensure ease of handling and longevity. Additionally, it should be resistant to moisture and chemicals to prevent degradation and maintain hygiene. Lastly, it should ideally be non-toxic and safe for food contact.
What type of adhesive should be used for installing tiles?
For installing tiles, it is recommended to use a thin-set mortar adhesive.
What adhesive should you use for linoleum?
Mapei Eco300 is my favorite .
Which container should you load bread crumbs in refer container or normal container?
You will want to use a refrigerated container to keep them from molding.
What object should you use for weighing food?
You use the scales.
What adhesive should I use to attach a sink to a vanity?
For attaching a sink to a vanity, it is recommended to use a strong adhesive specifically designed for bathroom fixtures, such as silicone adhesive or construction adhesive. These adhesives provide a secure and waterproof bond between the sink and vanity.
How Do you keep sugar art?
It should be kept in very dry, normal room temperature conditions. Use an air-tight container. For extra precaution place a substance in the container that will help to keep the art dry, such as silica gel. The warmer the temperature, the softer the sugar will become. ____________________________________________________________________________________________________
