Liquid sodium is being considered as an engine coolant. how many grams of liquid sodium (minimum) are needed to absorb 6.70 mj of energy (in the form of heat) if the temperature of the sodium is not to increase by more than 10.0 °c? use cp= 30.8 j/(k·mol) for na(l) at 500 k.

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500324 grams

Explanation:-

Heat absorbed Q = M x Cp x T

We are given T = 10 [ The maximum allowed temperature increase]

Plugging in the values

6.70 x 10^ 6 J = M x 30.8 J / (K mol) x 10 K

M = 6.70 x 10 ^6 / (30.8 x 10)

= 21753 moles

Atomic Mass of sodium =23 gram / mol

Grams of liquid sodium required = 21753 moles x 23 grams / mol

= 500324 grams

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answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e