Answer:
61.5096 %
Explanation:
Let the amount of gold in the jewelry = x g
Let the amount of silver in the jewelry = y g
Total mass of jewelry = 9.85 g
So,
x + y = 9.85 g .................................1
Density = Mass / Volume
Given that:
Density of gold = 19.3 g/cm³
Thus, volume is:
Volume = Mass / Density = x / 19..3 cm³
Given that:
Density of silver = 10.5 g/cm³
Thus, volume is:
Volume = Mass / Density = y / 10.5 cm³
The total volume of the jewelry = 0.675 cm³
So,
Or,
10.5 x + 19.3 y = 136.78875 ................2
Solving 1 and 2, we get that:
<u>x = 6.0587 g</u>
<u>y = 3.7913 g</u>
So, mass % of gold:
<u>Mass % = (6.0587 / 9.85)×100 = 61.5096 %</u>
Answer:
92 is that atomic number and 238.03 is the atomic mass number
Explanation:
The structure of the atom is given as:
⁹²₂₃₈.₀₃U
The number 92 is the atomic number of the atom.
The atomic number is the number of protons within an atom. This number defines the nature and type of atom that we have.
238.03 is the atomic mass number;
The is the number of protons and neutrons within an atom. It is typically the mass of nucleus.
Answer:
Einstein proposed that electromagnetic radiation has a wave-particle nature, that the energy of a quantum, or photon, depends on the frequency of the radiation, and that the energy of the photon is given by the formula Ephoton=hv.
47% yield.
First, let's determine how many moles of ethane was used and how many moles of CO2 produced. Start with the respective atomic weights.
Atomic weight carbon = 12.0107
Atomic weight hydrogen = 1.00794
Atomic weight oxygen = 15.999
Molar mass C2H6 = 2 * 12.0107 + 6 * 1.00794 = 30.06904 g/mol
Molar mass CO2 = 12.0107 + 2 * 15.999 = 44.0087 g/mol
Moles C2H6 = 8 g / 30.06904 g/mol = 0.266054387 mol
Moles CO2 = 11 g / 44.0087 g/mol = 0.249950578 mol
Looking at the balanced equation, for every 2 moles of C2H6 consumed, 4 moles of CO2 should be produced. So at 100% yield, we should have 0.266054387 / 2 * 4 = 0.532108774 moles of CO2. But we only have 0.249950578 moles, or 0.249950578 / 0.532108774 = 0.46973587 =
46.973587% of what was expected.
Rounding to 2 significant figures gives 47% yield.
