Which of the following temperatures is used as the reference for water density when calculating specific gravity?

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Multiple Choice

Which of the following temperatures is used as the reference for water density when calculating specific gravity?

Specific gravity uses a standard reference density for water, and that reference is taken at the temperature where water is densest. Water reaches its maximum density at about 4°C, roughly 1.0 g/cm^3. Using this temperature as the reference keeps SG values consistent and minimizes how much they change with temperature, since water would be slightly less dense at other temperatures. At 0°C or 20°C, the density of water is not 1.0 g/cm^3, which would tilt SG values, and at -40°C water can’t even be a liquid. So the reference temperature is 4°C.

Specific gravity uses a standard reference density for water, and that reference is taken at the temperature where water is densest. Water reaches its maximum density at about 4°C, roughly 1.0 g/cm^3. Using this temperature as the reference keeps SG values consistent and minimizes how much they change with temperature, since water would be slightly less dense at other temperatures. At 0°C or 20°C, the density of water is not 1.0 g/cm^3, which would tilt SG values, and at -40°C water can’t even be a liquid. So the reference temperature is 4°C.

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