Answer:
Explanation:
wavelength λ = 12.4 x 10⁻² m .
energy of one photon = h c / λ
= 6.6 x 10⁻³⁴ x 3 x 10⁸ / 12.4 x 10⁻²
= 1.6 x 10⁻²⁴ J .
Let density of coffee be equal to density of water .
mass of coffee = 255 x 1 = 255 g
heat required to heat up coffee = mass x specific heat x rise in temp
= 255 x 4.18 x ( 62-25 )
= 39438.3 J .
No of photons required = heat energy required / energy of one photon
= 39438.3 / 1.6 x 10⁻²⁴
= 24649 x 10²⁴
= 24.65 x 10²⁷ .
Answer: 
Explanation:
The balanced chemical equation :
To calculate the moles, we use the equation:

According to stoichiometry:
4 moles of
produces = 902.0 kJ of energy
415.1 moles of
produces =
of energy
Thus the change in enthalpy is 
PH and conductivity have no common rekationship
Answer: Servsafe 9
Explanation:
Remove food from the surface
clean the surface
rinse the surface
sanitize the surface
allow the surface to air dry
No of moles of naoh = 2.40 ÷ (23+16+1) = 0.06mol
no of moles of na2co3 = 0.06 ÷ 2 = 0.03mol
mass of na2co3 = 0.03 × (23×2+12+16×3) = 0.03 × 106 = 3.18g