Answer:
A. a new substance is being produced.
Explanation:
The bubbles most likely indicates that a new substance is being produced by this reaction. In essence, we describe this sort of change as chemical change.
In a chemical change, new substances are usually produced. They are accompanied by the evolution or absorption of energy.
The reaction of Zinc with a strong acid to produce bubbles on the surface of the metal indicates a chemical change and the formation of a new kind of substance.
Take for example, let zinc reacts with hydrocholoric acid, HCl;
Zn + 2HCl → ZnCl₂ + H₂
Since Zn is higher than Hydrogen in the activity series, it will displace it from HCl and liberate hydrogen gas as a product. This will cause the bubbles observed in the reaction.
This is a chemical change and new products have been formed.
B and D are wrong because they are both physical changes.
C is wrong because no information about such is provided by the problem statement.
So, when a piece of zinc metal combines with a strong acid, a new kind of substance is produced.
Answer:
The answer to your question is 1 M
Explanation:
Data
Molarity = ?
mass of CaCl₂ = 222.2 g
Volume = 2 l
Process
1.- Calculate the molar mass of CaCl₂
CaCl₂ = 40 + (35.5 x 2) = 40 + 71 = 111 g
2.- Calculate the moles of CaCl₂
111g of CaCl₂ ---------------- 1 mol
222.2 f of CaCl₂ ---------------- x
x = (222.2 x 1) / 111
x = 222.2 / 111
x = 2 moles
3.- Calculate the Molarity
Molarity = moles / Volume
-Substitution
Molarity = 2/2
-Result
Molarity = 1
Answer: It's colder.
Explanation: Well for starters Valparaiso is further away from the equator, and Australia is already really hot. But say that Valparaiso is further from the equator should be good enough.
Answer:
five half lives
Explanation:
Half-life is the time required for a quantity to reduce to half of its initial value.
How many half lives it would take to reach 3.13% form 100% of it's initial concentration:
100% - 50% : First Half life
50% - 25%: Second Half life
25% - 12.5%: Third Half life
12.5% - 6.25%: Fourth Half life
6.25% - 3.125%: Fifth Half life
This means it would take five half lives to get to 3.125% (≈ 3.13%) of it's original concentration.
