Answer:
The direction of an electric current is by convention the direction in which a positive charge would move. Thus, the current in the external circuit is directed away from the positive terminal and toward the negative terminal of the battery.
Explanation:
Another name for them are called groups or families.
Answer:
1.41x10⁻⁴ M
It will not attain the level recommended.
Explanation:
When the NaF is added to the water, it will dissociate, forming the ions Na⁺ and F⁻. The fluoride ion may react with the Ca⁺² ions to form the salt CaF₂, which can dissociate too. The dissociation, or solubilization, is characterized by the solubility product (Kps), which is an equilibrium constant. For CaF₂, Kps = 4.0x10⁻¹¹, so:
CaF₂(s) ⇄ Ca⁺² + 2F⁻(aq)
The solids are not put in the equilibrium expression, so:
Kps = [Ca⁺²] * [F⁻]²
4.0x10⁻¹¹ = 0.0020*[F⁻]²
[F⁻]² = 2.0x10⁻⁸
[F⁻] = √2.0x10⁻⁸
[F⁻] = 1.41x10⁻⁴ M
Which is the maximum concentration to the solution be saturated, after that, the solid will precipitated. Because the concentration of fluoride ion is lower than the recommended, it will not attain.
Answer:
676mmHg
Explanation:
Using the formula;
P1/T1 = P2/T2
Where;
P1 = initial pressure (mmHg)
P2 = final pressure (mmHg)
T1 = initial temperature (K)
T2 = final temperature (K)
According to the information provided in this question;
P1 = 725.0mmHg
P2 = ?
T1 = 20°C = 20 + 273 = 293K
T2 = 0°C = 0 + 273 = 273K
Using P1/T1 = P2/T2
725/293 = P2/273
Cross multiply
725 × 273 = 293 × P2
197925 = 293P2
P2 = 197925 ÷ 293
P2 = 676mmHg.
The resulting pressure is 676mmHg