Step one calculate the moles of each element
that is moles= % composition/molar mass
molar mass of Ca = 40g/mol, S= 32 g/mol , O= 16 g/mol
moles of Ca = 29.4 /40g/mol=0.735 moles, S= 23.5/32 =0.734 moles, O= 47.1/16= 2.94 moles
calculate the mole ratio by dividing each mole with smallest mole that is 0.734
Ca= 0.735/0.734= 1, S= 0.734/0.734 =1, O = 2.94/ 0.734= 4
therefore the emipical formula = CaSO4
Answer:
B
Explanation:
Reactants are the compounds which reaction produce the products. In general terms this can be expressed symbolically as follows:
reactants -> products
Other phenomena like heat are omitted because are not always present, that is, only compounds are included. Therefore, in this reaction the reactants are C3H8 (propane) and O2 ( oxygen) and the products are CO2 (carbon dioxide) and H2O (water)
Answer: A substance that produces hydroxide ions when placed in water is base.
Explanation:
Bases are the substance:
- Which gives negatively charged hydroxide(
) ions in aqueous solution.
- Which have pH value ranging from 7 to 14.
Where as acid gives positively charged hydronium ion(
) in aqueous solution.
In order to emit electrons, the cesium will have to absorb photons. Each photon will knock out one electron by transferring its energy to the electron. Therefore, by the principle of energy conservation, the energy of the removed electron will be equal to the energy of the incident photon. That energy is calculated using Planck's equation:
E = hf
E = 6.63 x 10⁻³⁴ * 1 x 10¹⁵
E = 6.63 x 10⁻¹⁹ Joules
The electron will have 6.63 x 10⁻¹⁹ Joules of kinetic energy
The equation relating velocity and wavelength is written below:
v = λf
where λ is the wavelength in m while f is frequency in 1/s.
Let's determine first the frequency from the speed of light:
c = distance/time, where c is the speed of light equal to 3×10⁸ m/s
3×10⁸ m/s = (300 mm)(1 m/1000 mm)/ time
time = 1×10⁻⁹ seconds
Since f = 1/t,
f = 1/1×10⁻⁹ seconds = 10⁹ s⁻¹
Thus,
v = (795×10⁻⁹ m)(10⁹ s⁻¹)
v = 795 m/s
