Salt lowers the freezing point and melting point of water/ice. Ice forms when water freezes and becomes 0 degree Celsius. When salt is added to ice, it dissolves into the liquid water within the ice and lowers that temperature and freezing point. “A 10-percent salt solution freezes at -6 Celsius, and a 20-percent solution freezes at -16 C.”
If one has ever watched salt melting ice, you can see the dissolving process happen, as the salt dissolves in the water and spreads out from the point first melted. Although, if the temperature of the roadway is lower than -9 Celsius or so, then the salt really won't have any affect the solid salt cannot get into the structure of the solid water to start the dissolving process.
Effect of Sand on Ice
Sand can melt ice if it is heated naturally from the sun or a warm temperature, just like all other substances that is at a higher temperature than ice. The actual texture of sand does not cause ice to melt. Sand, unless it is at a higher temperature than the ice, it would not melt.
Effect of Sugar on Ice
Fact: Sugar, and anything else that is able to dissolve in water, will melt ice. Like salt, sugar melts ice by lowering water's melting and freezing points. When sugar is added onto ice, it dissolves and interferes with the water molecules, which need to bind to ice crystals in order to freeze. Sugar’s presence needs the temperature to be much colder before the water molecules come into contact with ice crystals.
While sugar will melt ice, it still isn’t as effective as salt, which breaks down into sodium and chloride ions. When one molecule of salt dissolves, it adds two components to the solution, providing more interference in preventing water molecules from freezing.
Effect of Flour on Ice
“If you put flour in water, you make pancake batter which freezes at about the same temperature as water. So it won't melt ice at all.”
Conclusion: Sugar and salt lowers the freezing/melting pointing of water/ice,therefore making the ice melt. Although salt is more efficient when one molecule of salt dissolves,
it adds two components to the solution, providing more interference in preventing water molecules from freezing. Sand melts ice by providing traction and absorbing heat and being at a higher temperature than the ice, hence, melting it. Flour has no effect on ice, and may even serve as an insulator from the higher temperature that surrounds the ice.
The measurement of Rachel’s group is precise but not accurate while the measurement of Ashley’s group is accurate but not precise.
Precision has to do with how close together the values obtained from a scientific measurement is. If we take a look at the values obtained by Rachel’s group, we will notice that the values are exactly 1.00 g apart. This means that the values are precise.
However, these values a far from the actual value which is 100.00 g therefore the measurement of Rachel’s group is precise but not accurate.
On the other hand, the values obtained by Ashley’s group are; 99.5 g, 100.1 g, and 100.5 g. These values are very close to the actual value which is 100.00 g hence they are accurate.
The values obtained by Ashley’s group do not have consistent intervals therefore, they are not precise.
Learn more; brainly.com/question/15664210
<u>Answer:</u>
The mass of the atom depends on the sub atomic particles present in the nucleus of an atom.
That is, the protons and the neutrons.
Electrons are present around the nucleus and the mass is negligible since its mass is very very less.
<em>mass of a proton = 
</em>
<em>mass of a neutron = 
</em>
<em>mass of an electron = 
</em>
Mass number represents the mass of one particular isotope and it is a whole number for example, 
Mass number is 13 and atomic number is 6 for the carbon isotope C-13.
Atomic mass is different from mass number and it is a fraction since it is the average atomic mass of all the isotopes of an atom.
Atomic mass of C is 12.011 amu which we see in the periodic table is the average atomic mass of isotopes C-12, C-13 and C-14.
Colligative properties depend on the amount of solute dissolved in a solvent. These set of properties do not depend on the type of species present. These properties include freezing point depression, boiling point elevation, osmotic pressure and vapor pressure lowering.
