Answer:
d. Radon-222
Explanation:
²²⁶₈₈Ra → ²²²₈₆Rn + ⁴₂He
Alpha particle is a helium nucleus with mass number 4 and atomic number 2. According to the law of conversation of mass, the sum of the mass number and atomic number must be equal on both side of the reaction.
Since the mass number of Ra is 226 and that of He is 4. The mass number of the unknown element must be 226 - 4 = 222.
Since the atomic number of Ra is 88 and that of He is 2. The atomic number of the unknown element must be 88 - 2 = 86.
Now looking in the periodic table Radon is the only element with atomic number 86.
When a water vapor condenses, heat is being released from the process. This heat is called latent heat of vaporization since the phase change happens without any change in the temperature. This value is constant per mole of a substance as a function of pressure and temperature. For this problem, we are given the heat of vaporization at a certain T and P. We use this value to calculate the total heat released from the process. We calculate as follows:
Total heat released: 32.4 g ( 1 mol / 18.02 g ) (40.67 kJ / mol) = 73.12 kJ
Therefore, 73.12 kJ of heat is released from the condensation of 32.4 g of water vapor.
Answer:
C. Earth's revolution around the sun
Explanation:
The formula of alcohol are
1.913 g CO2/44 = 0.043 moles of CO2*12 = 0.043 moles of C 1.174 gram H2O/18 = 0.065 moles of H.
O: 1 - 0.516 g C - 13 g H = 0.354 g O/16 = 0.022 moles of O.
we have 0.043:0.130.;0.022 as C:H:O. Diving by the smallest no. 0.022 we get 1.95:5.9:1 or 2:6:1 as C:H:O.
hope this help
The rule that says electrons are added to the lowest energy level first.
