Answer:
False. Chemical changes are always physical changes
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To measure the volume of an acid we use in the laboratory an instrument called burette (a). This instrument is used to calculate the volumes of chemical solutions. At first glance, these tools may be confused with syringes, but have different functions.
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Explanation:
A mixture in which there is uniform distribution of solute particles into the solvent is known as a homogeneous mixture.
For example, sugar dissolved in water is a homogeneous mixture.
On the other hand, a mixture in which there is uneven distribution of solute particles into the solvent is known as a heterogeneous mixture.
For example, sand present in water is a heterogeneous mixture.
Comment on given situations will be as follows.
(a) Air in a closed bottle - It is a homogeneous mixture because there will be even distribution of other gases that are present in air.
(b) Air over New York City - It is a heterogeneous mixture because there will be presence of some dust particles, fog or smoke into the air. Distribution of all these particles will be uneven. This will make air over New York City heterogeneous in nature.
Answer:
Option B. It is a basic solution.
Explanation:
To know which option is correct, let us calculate the pH of the solution.
First, we shall determine the pOH of the solution. This is illustrated below:
Concentration of Hydroxide ion, [OH¯] = 3.5×10¯⁶
pOH =.?
pOH = –Log [OH¯]
pOH = –Log 3.5×10¯⁶
pOH = 5.5
Finally, we shall determine the pH. This can be obtained as follow:
pOH = 5.5
pH =?
pH + pOH = 14
pH + 5.5 = 14
Collect like terms
pH = 14 – 5.5
pH = 8.5
The pH scale reads as follow:
0 to 6 => Acidic
7 => Neutral
8 to 14 => Basic
Comparing the pH of the solution (i.e 8.5) with the pH scale, we can conclude that the solution is basic because the pH of solution lies between 8 and 14.
