Question

If 100.00 J are added to 20.0 g water at 30.0°C, what will be the final temperature of the water?

Answer 1

The final temperature of the water will be 31.2 °C.

Explanation:

The formula for the heat gained or lost by a substance is

`color(blue)(bar(ul(|color(white)(a/a)q = mcΔTcolor(white)(a/a)|)))" "`

We can rearrange this equation to get

`ΔT = q/(mc)`

In this problem,

`q = "100.00 J"`
`m = "20.0 g"`
`c = "4.178 J·K"^"-1""g"^"-1"`

`ΔT = (100.00 color(red)(cancel(color(black)("J"))))/(20.0 color(red)(cancel(color(black)("g"))) × "4.178 J"·color(red)(cancel(color(black)("K"^"-1""g"^"-1")))) = "1.197 °C"`

`ΔT = T_"f" - T_"i" = T_"f"color(white)(l) "- 30.0 °C" = "1.197 °C"`

`T_"f" = "30.0 °C + 1.197 °C" = "31.2 °C"`