Negtive
The sign only depends on whether it's an exothermic or endothermic reaction. So no, it doesn't depend on phase change, and in some reactions, there is no phase change. But you will find correlation between the sign and the direction of the phase change because they will either be endothermic or exothermic. The enthalpy of fusion is positive because melting is an endothermic reaction (think - you put in heat to melt an ice cube). Endothermic reactions are represented by positive enthalpy. Conversely, freezing is an exothermic process (heat is taken out of the molecules in order to slow them down). We represent exothermic reactions with negative enthalpy.Always be conscious of the sign when working with thermochemistry calculations. Unlike the usual math, the signs of these numbers are somewhat arbitrary. We say that the system is losing heat in an exothermic reaction; thus, the energy must be represented by a negative. However, there are a few areas (like electrical engineering) where an exothermic reaction is represented by a positive number (because usually the goal is to produce heat).
melting ice a physical change
What you need is the enthalpy of fusion for ice and simply multiply it by your mass. An online search shows that the enthalpy of fusion for ice is: 79.72 cal/g So calories needed to melt all your ice is just. Energy = 79.72cal/g x 25g = 242.50 calories
melting ice a physical change
melting ice a physical change
There are two tendencies in nature: things tend to go to the lowest possible energy (enthalph) level (delta H = negative) and the highest possible state of disorder (entropy)
its the latent heat of fusion or simply Enthalpy of fusion.ie,this heat is absorbed or added at melting temperature.for eg latent heat of fusion of ice= 6.02 KJ/mol (80cal/gm).
Melting ice turns the ice into water.
The sign only depends on whether it's an exothermic or endothermic reaction. So no, it doesn't depend on phase change, and in some reactions, there is no phase change. But you will find correlation between the sign and the direction of the phase change because they will either be endothermic or exothermic. The enthalpy of fusion is positive because melting is an endothermic reaction (think - you put in heat to melt an ice cube). Endothermic reactions are represented by positive enthalpy. Conversely, freezing is an exothermic process (heat is taken out of the molecules in order to slow them down). We represent exothermic reactions with negative enthalpy.Always be conscious of the sign when working with thermochemistry calculations. Unlike the usual math, the signs of these numbers are somewhat arbitrary. We say that the system is losing heat in an exothermic reaction; thus, the energy must be represented by a negative. However, there are a few areas (like electrical engineering) where an exothermic reaction is represented by a positive number (because usually the goal is to produce heat).
it is relatively large
melting ice a physical change
You get a "+1" for being on the ice when your team scores and a "-1" when your on the ice when the opposing team scores
ice melting is a physical reaction
both. no plant can live without it, having to use photosynthesis to get food. there are also downsides, the polar ice caps are melting which is causing the sea level to rise therefore changing the weather Also it has no charge it's a compound not an ion.
What you need is the enthalpy of fusion for ice and simply multiply it by your mass. An online search shows that the enthalpy of fusion for ice is: 79.72 cal/g So calories needed to melt all your ice is just. Energy = 79.72cal/g x 25g = 242.50 calories
Ice cream are do melting because it are because hot.
melting ice a physical change