Answer:
The fact that most alpha particles went straight through the foil is because the atom is mostly empty space.
Those that passed straight through did so because they didn't encounter any nuclei.
Explanation:
Answer:
No. Of Moles of zinc = m/Ar
= 13/ 65.38 = 0.198 moles
From balanced equation, Mole ration between CuSO4 and Zn is 1 : 1
So only 0.198 moles of CuSO4 reacts, it is in excess
Mass = no of Moles X Mr
Mass = 0.198 X 159.5 = 31.59 grams
Volume = mass m denisty
Volume j 31.59 / 3.6 = 8.78 ml
Explanation:
i think this wrong
Answer:
Electromagnetic radiation is a form of energy that is produced by oscillating electric and magnetic disturbance, or by the movement of electrically charged particles traveling through a vacuum or matter. The electric and magnetic fields come at right angles to each other and combined wave moves perpendicular to both magnetic and electric oscillating fields thus the disturbance. Electron radiation is released as photons, which are bundles of light energy that travel at the speed of light as quantized harmonic waves. This energy is then grouped into categories based on its wavelength into the electromagnetic spectrum. These electric and magnetic waves travel perpendicular to each other and have certain characteristics, including amplitude, wavelength, and frequency.
General Properties of all electromagnetic radiation:
Electromagnetic radiation can travel through empty space. Most other types of waves must travel through some sort of substance. For example, sound waves need either a gas, solid, or liquid to pass through in order to be heard.
The speed of light is always a constant. (Speed of light : 2.99792458 x 108 m s-1)
Wavelengths are measured between the distances of either crests or troughs. It is usually characterized by the Greek symbol λ .
Explanation:
i really dont know but this is what i thin it is
Answer: The empirical formula is 
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mas of H = 1.8 g
Mass of S = 56.1 g
Mass of O = 42.1 g
Step 1 : convert given masses into moles.
Moles of H =
Mass of S =
Moles of O=
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For H = 
For S =
For O =
Converting to whole number ratios
The ratio of H: S: O= 2: 2: 3
Hence the empirical formula is
Answer:
- <u><em>It is positive when the bonds of the product store more energy than those of the reactants.</em></u> (the second statement)
Explanation:
ΔHf is the change of enthalpy during the reaction, which is equal to the sum of enthaply changes of the products less the sum of the enthalpy changes of the reactants.
- ΔHf = ∑ (ΔH products) - ∑ (ΔH reactants)
Also, ΔHrxn, per definition, is the potential chemical energy stored in the bonds of the products less the chemical potential energy stored in the bonds of the reactants.
Then, when the potential chemical energy stored in the bonds of the products is greater than the chemical potential energy stored in the bonds of the reactants ΔHrxn is positive.
Hence, you conclude that ΔHf is positive when the bonds of the product store more energy than those of the reactants (second statement from the choices).
Some brief comments about the other statements:
- The standard enthalpy of formation, ΔHf, is zero for an element in its standard state, not for a compound.
- For a compound the enthalpy of formation at 25ºC and 1 atm (the standard state) may be positive or negative.
- Also, note that the standard state for any element is not liquid: some are solids, some are gases, and some are liquids at 25ºC and 1 atm.
