Answer:
4m/s in the direction of the turn
Explanation:
The velocity of an object is the rate of change of its position with respect to a frame of reference.
Assuming the runner stays the same speed as he turns, his velocity will be 4m/s in the speed he turns.
Answer:
It depends what other values you have. Can you give more info? If they give density then you can solve for m.
Answer:
you must add 50 mL
Explanation:
Hi
KOH is a strong base and by adding 100mL 0.05M you will have an amount of 5 millimol.
NaCN is a base and by adding 50 mL 0,150 M you will have an amount of 7,5 mmol.
HCl is a acid and by adding 200 mL 0,075 M you will have an amount of 15 mmol.
The acid reacts with the bases leaving 2.5 mmol unreacted.
Na3PO4 is a base and by adding 50 mL 0,1 M you will have an amount of 5 mmol.
The 2.5 mmol of acid react with the base PO4 ^ -3 forming a regulatory solution of PO4 ^ -3 and HPO4 ^ -2 of pKa 2.12
5 mmol of acid (HNO3) must be added to obtain a regulatory solution formed by the same amount of HPO4 ^ -2 (2.5 mmol) and H2PO4 ^ -1 (2.5 mmol) with pKa 7.21
Considering a quantity of 5 mmol of HNO3 of concentration 0.1 M, 50 mL must be added.
To calculate the pH of the regulatory solution you should consider pH = pKa × Ca / Cb pH = 7.21 × 2.5 / 2.5 = 7.21 Being in the same solution the volume is the same and can be simplified to achieve a faster calculation.
successes with your homework
Suppose X (in unit M) be the required maximum concentration of the Pb(NO₃)₂ solution added after mixing with 100 ml of 6.5 x 10⁻² M NaCl, the Pb²⁺ concentration is:
[Pb²⁺] = (X*100) / 200 = 0.5 X
The concentration of Cl⁻ is:
[Cl⁻] = (100 / 200) * (6.5 x 10⁻² M) = 0.0325 M
So:
Ksp = 2.00 x 10⁻⁵ = [Pb²⁺] [Cl⁻]² = (0.5X) * (0.0325)²
X = (2.00 x 10⁻⁵) / (5.28 x 10⁻⁴) = 0.038 M
