Of the following, which does not signify a chemical reaction?
1) tarnish
2) release of heat
3) changing state
4) release of gas
Of the following, which does not signify a chemical reaction?
1) tarnish
2) release of heat
3) changing state
4) release of gas
A blue liquid is mixed into a yellow liquid, and the mixture turns green.
A piece of metal is placed in water and produces sparks and gas.
A liquid is heated on a hotplate, and bubbles form.
Explanation:
A chemical reaction occurs when reactants combine or decompose to form products which have a completely different composition and structure than the reactants. There are certain signs which indicate that a chemical reaction has taken place, the primary indicators include:
1) Formation of a precipitate
2) Formation of bubbles
3) color change
4) change in temperature
Based on the given examples:
1) A blue liquid is mixed into a yellow liquid, and the mixture turns green:
This involves a color change and hence a chemical process
2) A piece of metal is placed in water and produces sparks and gas.
Formation of sparks and gas signify a change in temperature and hence a chemical process
3) A liquid is heated on a hotplate, and bubbles form.
Formation of bubbles are indicate that a chemical reaction has occured
2
Explanation:
release of heat is a chemical reaction that releases energy
A liquid is heated on a hot plate, and bubbles form
I believe it’s D.
Explanation:
B) A piece of metal in water and produces spark and gas
2. A piece of metal is placed in water and produces sparks and gas
Explanation:
The production of gas is usually a sign of a chemical reaction. The metal is reacting with the water to form a new substance (the gas).
Incorrect answers and why:
1. Changing colors can be a sign of a chemical reaction, but in this case it's more likely that the colors blended together. (If it was something like two clear liquids combining to form a yellow liquid, then it would be more clear evidence of a chemical reaction)
3. The liquid is boiling
4. The powder dissolved into the liquid
I hope this helps!
1. Change in temperature
2. Gas given off (bubbles)
3. Color change
4. Salts made
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A solid forms when two liquids are mixed.
Explanation:
A physical reaction is defined as the reaction in which a change in shape, size takes place. No new substance gets formed in these reactions.
A chemical reaction is defined as the reaction in which a change in chemical composition takes place. A new substance is formed in these reactions.
1. A solid dissolves in liquid: Only the phase of the solid changes to aqueous and no new substance is formed, thus is a physical change.
2. A solid forms when two liquids are mixed: two liquids can forma solid only on chemical combination and formation of new substance.
3. A solid melts to a liquid when it is heated: Only the phase of the solid changes to liquid, no new substance is formed, thus is a physical change.
4. A solid metal changes shape: Only the shape of the solid changes, thus is a physical change.
i think its A
Explanation:
the properties of product formed
All of them do. The last one could be dissolution, though.