In a beaker, sugar is dissolved in water, and then the water is heated and evaporates. The sugar is recovered, and heat is again applied. Vapor is released, and the material in the beaker changes from white to black. What must you know to determine if a chemical change occurred?
the boiling point of waters
the boiling point of sugar
the temperature at which sugar evaporates
whether or not the black substance is sugar
1.the boiling point of waters
2.the boiling point of sugar
3.the temperature at which sugar evaporates
4.whether or not the black substance is sugar
2007-06-15 20:14:15 · 5 answers · asked by CDM 1 in Science & Mathematics ➔ Chemistry
4.
In the first part of the experiment, the sugar retained its chemical form; even after the water is gone, the substance is white, which is what sugar should be. In the second part, what remains in the beaker is black, meaning it is no longer sugar (it is in fact carbon). The only way for that to happen is for a chemical change to occur.
2007-06-15 20:19:00 · answer #1 · answered by gp4rts 7 · 0⤊ 0⤋
4. Whether or not the black substance is sugar.
The boiling points of water or sugar are not relevant in chemical changes because any change of state (freezing from liquid to solid, evaporating from liquid to gas) is NOT a chemical change; it is a physical change. In chemical changes, a new substance is always being produced. So, in order to determine if a chemical change has occurred, you need to know if that black substance is a new substance with a new chemical composition, different from sugar.
2007-06-16 06:13:53 · answer #2 · answered by Anonymous · 0⤊ 0⤋
4) whether or not the black substance is sugar.
because chemical reactions usually result in new substances formed
2007-06-16 07:59:06 · answer #3 · answered by kiwi 2 · 0⤊ 0⤋
How can you be a Christian without proving the existence of the Creator to yourself? I am an Echatologist. And I am a Christian. I am concerned about proving the existence of God to myself. But have never been moved to become involved in proving Christianity by His existence......... because all I have to do is look around me...... Christianity is an undeniable reality. Not a very pretty one granted....... (its conduct would be a subject for a different time) I can see the merit of your question challenging the existence of a Christian God....... I am not following the logic...... unless God's existence for some reason marks a particlar brand of Christianity as be the only true one???? And that logic would be silly. So after reading the question's added details again and again this is what I think you are saying..... "Why do Christians make God into a Christian God." when there are so many other "flavors" of God out there? Because they believe they understand correctly who He is?? My guess. Michelle
2016-05-17 06:17:11 · answer #4 · answered by Anonymous · 0⤊ 0⤋
by the chng in col the black substance is sugar
2007-06-15 20:32:18 · answer #5 · answered by siddarth k 1 · 0⤊ 0⤋