Aphoton has a frequency of 2.9 × 10–16 hz. planck’s constant is 6.63 × 10–34 j•s. the energy of the photon, to the nearest tenths place, × 10–49 j.

Ans: E = 1.9 *10⁻⁴⁹ J

Given:

Frequency of photon, ν = 2.9 *10⁻¹⁶ Hz

planck's constant, h = 6.63*10⁻³⁴ Js

To determine:

The energy (E) of photon

Explanation:

Energy is related to the frequency by:

E = hν

   = 6.63*10⁻³⁴ Js * 2.9 *10⁻¹⁶ s-1

   = 1.9 *10⁻⁴⁹ J

b i think it’s a water wheel turning in a stream

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.