Frequency = speed of light/wavelength
speed of light = ~ 3 x 10^8 m/s.
Answer:
See explanation
Explanation:
I believe that the aim of the scientist is to determine the effect of a cancer drug on mice with lymphoma. In this experiment, the mice with lymphoma are exposed to the drug. This is the treatment in the experiment. A control group of mice having lymphoma is not exposed to this treatment, this is the control group. This control group establishes a baseline for the study.
By comparing the outcome of the experimental and control groups, the effect of a cancer drug on mice with lymphoma can be determined.
Answer:
HCOOH(aq) + OH-(aq) —> HCOO-(aq) + H2O(l)
Explanation:
HCOOH is a weak acid and so will not ionised completely in solution.
KOH is a strong base and will ionised completely as shown below
KOH(aq) –> K+(aq) + OH-(aq)
The overall reaction can be written as follow:
HCOOH(aq) + K+(aq) + OH-(aq) —> HCOO-(aq) + K+(aq) + H2O(l)
Cancel out the K+ to obtain the net ionic equation as shown below
HCOOH(aq) + OH-(aq) —> HCOO-(aq) + H2O(l)
In a covalent bond, the atoms bond by sharing electrons. Covalent bonds usually occur between nonmetals. For example, in water (H2O) each hydrogen (H) and oxygen (O) share a pair of electrons to make a molecule of two hydrogen atoms single bonded to a single oxygen atom.
Answer:
a) +640 kJ/mol or +1.06x10⁻¹⁸ J
b) +276 kJ/mol
Explanation:
To dissociate the molecule, the bond must be broken, thus, it's necessary energy equal to the energy of the bond, which can be calculated by:
E = (Q1*Q2)/(4*π*ε*r)
Where Q is the charge of the ions, ε is a constant (8.854x10⁻¹²C²J ⁻¹ m⁻¹), and r is the bond length. Each one of the ions has a charge equal to 1. The elementary charge is 1.602x10⁻¹⁹C, which will be the charge of them.
1 mol has 6.022x10²³ molecules (Avogadros' number), so the energy of 1 mol is the energy of 1 molecule multiplied by it:
E = 6.022x10²³ *(1.602x10⁻¹⁹)²/(4π*8.854x10⁻¹²*2.17x10⁻¹⁰)
E = +640113 J/mol
E = +640 kJ/mol
Or at 1 molecule: E =640/6.022x10²³ = +1.06x10⁻²¹ kJ = +1.06x10⁻¹⁸ J
b) The energy variation to dissociate the molecule at its neutral atoms is the energy of dissociation less the difference of the ionization energy of K and the electron affinity of F (EA):
498 = 640 - (418 - EA)
640 -418 + EA = 498
222 + EA = 498
EA = +276 kJ/mol
