A heating fan is supplied with 150 j of electricity which is nonverts to 113 j of thermal energy and 37 j of sound energy How efficient is the heating fan?

Heating Fan is 75.33% efficient.

Explanation:

As it is mentioned that the given fan is a HEATING FAN, it means the it is used for provided heat (thermal energy) to the surrounding. Hence, its efficiency depends upon how much heat/thermal energy is provides.

We can state that.

Total Energy provided = 150 J

Useful Energy = 113 J

Wasted Energy = 37 J

The efficiency of the heating fan can be given by following formula:

Efficiency = ( Useful Energy / Total Energy ) × 100

Efficiency = ( 113 J / 150 J) × 100

Efficiency = (0.7533)× 100

Efficiency = 75.33%

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

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.