Answer:
Dissolving sugar in water, burning paper, and melting gold are all chemical changes
Explanation:
The action cannot be reversed, or undone. Therefore it is a chemical change.
Boiling water is a physical change.
The balanced chemical reaction for the described reaction above is,
Na2CO3 + 2HCl ---> 2NaCl + H2CO3
From the reaction, 1 mole of Na2CO3 is needed to produce 2 moles of NaCl. In terms of mass, 106 grams of Na2CO3 are needed to produce 116.9 grams of NaCl. From this,
(23.4 g NaCl) x (106 g Na2CO3 / 116.9 NaCl = 21.22 g Na2CO3
Thus, approximately 21.22 g Na2CO3 is needed for the desired reaction.
Answer:
1M HCl: add 1mol/12M = 83 ml conc. HCl to 1L of water or 8.3ml to 100ml.
2M HCl: add 2mol/12M = 167 ml conc. HCl to 1L of water or 16.7ml to 100ml.
<h2>Question↷</h2>
Which of these solutions is the most basic?
[OH-] = 4.3 x 10-9 M
[OH-] = 2.8 x 10-11 M
[OH-] = 6.7 x 10-10 M
[OH-] = 1.0 x 10-5 M
<h2>Answer↷</h2>
- <u>[OH-] = 1.0 x 10-5 M</u> ✓
<h2>Solution↷</h2>
[OH-] = 4.3 x 10-9 M
- [OH-] = 4.3 x 10^-9 M
- pOH = - log [OH^1-]
- pOH = - log [4.3 x 10^-9]
- pOH = 8.36
- pH = 14- 8.36
- pH = 5.64
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[OH-] = 2.8 x 10-11 M
- [OH-] = 2.8 x 10^-11 M
- pOH = - log [OH^1-]
- pOH = - log [2.8 x 10^-11 ]
- pOH = 10.55
- pH = 14-10.55
- pH = 3.45
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[OH-] = 6.7 x 10-10 M
- [OH-] = 6.7 x 10^-10 M
- pOH = - log [OH^1-]
- pOH = - log [6.7 x 10^-10]
- pOH = 9.17
- pH = 14-9.17
- pH = 4.83
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[OH-] = 1.0 x 10-5 M
- [OH-] = 1.0 x 10-5 M
- pOH = - log [OH^1-]
- pOH = - log [1.0 x 10^-5 ]
- pOH = 5
- pH = 14-5
- pH = 9
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we know that , the solution with <u>pH > 7</u> is termed as basic and more the pH ,more the basicity, hence ,the solution with the highest pH would be the strongest base out of these all which is
<u>[OH-] = 1.0 x 10-5 M</u> with pH = 9
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