Empirical Formulae for;
Compound 1- K5 Mn5 O16
Compound 2- Na2 Cr2 O7
Compound 3- C3 H4 O4
Compound 4- C3 H3 O1
Explanation:
Step 1; as all the element percentages are given in percent assume the total mass of the compound is 100g and take each percentage as grams i.e., 27.5% of K as 27.5 g of K and so on.
Step 2; convert the mass of each element into their mole values by dividing available mass by molar masses.
Molar masses of required elements are as follows; K=39, Mn=55, O=16 C=12, H=1, Na=23, Cr=52.
Step 3; Divide all the values by the smallest mole value. I.e. for compound 1 after dividing the masses by molar masses we get 0.705, 0.681, and 2.187 for elements K, Mn, O respectively. Divide all three values with the least value which is 0.681 and write these values down.
Step 4; Convert all the numbers available into whole numbers by multiplying with suitable values. i.e. 3 if values are 0.33, 2 if values are 0.5 etc.
Step 5; Assign these values to corresponding elements and you will get the above empirical formula.
The reported number of moles will be too low since the additional amount of oxygen is not included. It may be 6 drops but the molarity of the solution is 6M. this meas that for every ml of the JNO3 solution there is 6 moles of JNO3. In every mole of <span>JNO3 there are 3 moles of oxygen. So in every drop of oxygen there are 18 moles of oxygen. </span>
Answer : The frequency of a photon of radiation is, 
Explanation : Given,
Wavelength of the radiation = 670.8 nm
First we have to convert wavelength form 'nm' to 'm'.
Conversion used : 
So, the wavelength of the radiation = 670.8 nm = 
Now we have to calculate the frequency of a photon of radiation.
Formula used : 
where,
= frequency of a photon of radiation
= wavelength of the radiation
c = speed of light = 
Now put all the given values in the above formula, we get the frequency of a photon of radiation.


Therefore, the frequency of a photon of radiation is, 
Answer:
72.6 grams
Explanation:
I got this answer through stoichiometry. For every 1 mole of Mg, 2 moles of CuBr are consumed. Because of this, multiply the moles of Mg by 2. Then, convert moles to grams.