Explanation:
when an iron bar rust is an example of a chemical change in which a new substance is formed and the change is not easily reversible.for iron to rust moisture and air must be present.while when a substance freezes,it can be easily reversed through melting and no new substance is formed.this change is termed a physical change.
I don't know what the problem is, but here are some rues to help you out:
- All non-zero figures are significant
- When a zero falls between non-zero digits, that zero is significant.
- When a zero falls after a decimal point, that zero is significant.
- When multiplying and dividing significant figures, the answer is limited to the number of sig figs equal to the least number of sig figs in the problem.
- When adding and subtracting, the answer is limited to the number of decimal places in the number with the least number of decimal places.
Percent strength (% w/w) of a solution is defined as the amount of solute present in 100 g of the solution.
Given data:
Mass of the solute, potassium chloride = 62.5 g
Volume of water (solution) = 187.5 ml
We know that the density of water = 1 g/ml
Therefore, the mass corresponding to the given volume of water
= 187.5 ml * 1 g/1 ml = 187.5 g
We have a solution of 62.5 g of potassium chloride in 187.5 g water
Therefore, amount of solute in 100 g of water= 62.5 * 100/187.5 = 33.33
The percentage strength = 33.33 %
Answer:
To calculate the percentage of a specific number, you first convert the percentage number to a decimal. This process is the reverse of what you did earlier. You divide your percentage by 100. So, 40% would be 40 divided by 100.
Explanation:
The correct matches are as follows:
<span>1.instantaneous combustion
</span>G.burning<span>
2.mass of substances before and after a reaction is the same
</span>C.Law of Conservation of Matter<span>
3.substances that combine
</span>A.reactants
<span>
4. Yields or makes
</span>B.arrow symbol
<span>
5.rapid oxidation
</span>F.explosion<span>
6.new substance
</span>D.product
<span>
7.slow oxidation
</span>E.rust
<span>
Hope this answers the question. Have a nice day.
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