Wavelength = 434nm = 434 x 10⁻⁹m
planck's constant = <span>h= 6.626 x 10 ⁻³⁴ J
E =?
by using the formula;
E = hc /</span>λ
value for c is 3 x 10⁸ m/s
E = (6.626 x 10 ⁻³⁴ J)(3 x 10⁸ m/s) / 434 x 10⁻⁹m
E = 1.9878 x 10⁻²⁵ / 434 x 10⁻⁹m
E = 4.58 x 10⁻¹⁹ joules
Answer: B (to provide a statement that can be tested with an experiment
Explanation:
The more reactive element replaces less reactive element during chemical reaction.
Since, potassium is more reactive than beryllium. When potassium reacts with beryllium choride, it replaces beryllium and forms potassium chloride and produces beryllium.
Answer:

Explanation:
1. Write the balanced chemical equation.

2. Calculate the moles of HCOOH

3. Calculate the moles of NaOH.

4. Calculate the volume of NaOH

100.133 degree celsius is the boiling point of the solution formed when 15.2 grams of CaCl2 dissolves in 57.0 g of water.
Explanation:
Balanced eaquation for the reaction
CaCl2 + 2H20 ⇒ Ca(OH)2 + HCl
given:
mass of CaCl2 = 15.2 grams
mass of the solution = 57 grams
Kb (molal elevation constant) = 0.512 c/m
i = vont hoff factor is 1 as 1 mole of the substance is given as product.
Molality is calculated as:
molality = 
= 
= 0.26 M
Boiling point is calculated as:
ΔT = i x Kb x M
= 1 x 0.512 x 0.26
= 0.133 degrees
The boiling point of the solution will be:
100 degrees + 0.133 degrees (100 degrees is the boiling point of water)
= 100.133 degree celcius is the boiling point of mixture formed.