The battery itself contains chemical energy, which is converted to electrical energy, and then converted to mechanical energy.
Elements of Group 1 and group 2 in the periodic
table contain elements so reactive that they are never found in the free state
<u>Explanation</u>:
The metals in group 1 of periodic table consisting of 'alkali metals' which include lithium, potassium, sodium, rubidium, Francium and caesium. They are highly reactive because they have low ionisation energy and larger radius. The group 2 metals consist of 'alkaline earth metals' which include calcium, strontium, barium, beryllium, radium and magnesium. These alkaline earth metal have +2 oxidation number, hence are highly reactive.
These both group metals are mostly reactive and so are never found in a free state. When they are exposed to air they would immediately react with oxygen. Hence, are stored in oils to avoid oxidation.
Answer:
(1) See below, (2) About 8.4 pH, (3) About 3.981 * 10⁻⁶ mol dm⁻³
Explanation:
1. A buffer is a solution that resist pH when adding a basic or acidic compound. It's purpose is to neutralize added acids and bases.
2. Remember that the formula for pH is -log [H+]. We have a 0.1 M solution of baking soda in water with [H+] of about 4.0 × 10⁻⁹. Therefore we can calculate the pH as follows...
pH = -log (4.0 × 10⁻⁹)
pH = -(-8.39794...) = (About) 8.4 pH of 0.1 M of baking soda
3. This question has a similar set up...
pH = -log [H+]
[H+] = inverse of log^- pH
[H+] = 10^-5.4 = (About) 3.981 
10⁻⁶
Answer:
50mL of 4M NaCl, 80mL of 40% glucose, 20mL of 1M Tris-HCl (pH 8.5) and 250mL of water.
Explanation:
To make 400mL containing 0.5M NaCl you need to add:
4M / 0.5M = 8 (dilution 1/8). 400mL / 8 = <em>50 mL of 4M NaCl.</em>
Glucose 8% you need to add:
40% / 8% = 5 (dilution 1/5). 400mL / 5 = <em>80 mL of 40% glucose </em>
Buffer 50mM you need to add:
1000mM / 50mM = 20 (dilution 1/20). 400mL / 20 = <em>20mL of 1M Tris-HCl (pH 8.5)</em>
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The resting volume: 400mL - 50mL of 4M NaCl - 80mL of 40% glucose - 20mL of 1M Tris-HCl (pH 8.5) = 250 mL must be completed with water.
Thus, to make the solution you need: <em>50mL of 4M NaCl, 80mL of 40% glucose, 20mL of 1M Tris-HCl (pH 8.5) and 250mL of water.</em>
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I hope it helps!
