Use blue litmus paper. This is an indicator that can safely determine whether it is a base or an acid by changing color in response to the substance. This color indicates whether it is an acid or a base. Refer to the pH scale to see if the substance is basic or acidic.
Answer:
- The molarity of the student's sodium hydroxide solution is 0.0219 M
Explanation:
<u>1) Chemical reaction.</u>
a) Kind of reaction: neutralization
b) General form: acid + base → salt + water
c) Word equation:
- sodium hydroxide + oxalic acid → sodium oxalate + water
d) Chemical equation:
- NaOH + H₂C₂O₄ → Na₂C₂O₄ + H₂O
b) Balanced chemical equation:
- 2NaOH + H₂C₂O₄ → Na₂C₂O₄ + 2H₂O
<u>2) Mole ratio</u>
- 2mol Na OH : 1 mol H₂C₂O₄ :1 mol Na₂C₂O₄ : 2 mol H₂O
<u>3) Starting amount of oxalic acid</u>
- mass = 28 mg = 0.028 g
- molar mass = 90.03 g/mol
- Convert mass in grams to number of moles, n:
n = mass in grams / molar mass = 0.028 g / 90.03 g/mol = 0.000311 mol
<u>4) Titration</u>
- Volume of base: 28.4 mL = 0.0248 liter
- Concentration of base: x (unknwon)
- Number of moles of acid: 2.52 mol (calculated above)
- Proportion using the theoretical mole ratio (2mol Na OH : 1 mol H₂C₂O₄)

That means that there are 0.000622 moles of NaOH (solute)
<u>5) Molarity of NaOH solution</u>
- M = n / V (liter) = 0.000622 mol / 0.0284 liter = 0.0219 M
That is the correct number using <em>three signficant figures</em>, such as the starting data are reported.
The hypothesis should be; "Increasing the amount of ice increases the rate at which the ice will melt"
<h3>What is a hypothesis?</h3>
The term hypothesis refers to a tentative explanation that could be applied in order to explain an observation. When we give a hypothesis, it must be subjected to rigorous experimentation thus it can be confirmed or repelled by experiment.
Now, we can see that the question here is; "How does the amount of salt added to ice affect the rate at which the ice will melt?" This implies that the correct hypothesis here ought to have to do with the impact of the amount of ice in the affirmative.
Thus, the hypothesis should be; "Increasing the amount of ice increases the rate at which the ice will melt"
Learn more about hypothesis:brainly.com/question/13025783
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An object on the moon is 1/6 of the weight of an object on Earth
To find the answer to your question, divide the number of N on Earth by 6, 6N / 6 = 1N
Hope this helps!