Answer:Rule 1: The oxidation number of an element in its free (uncombined) state is zero — for example, Al(s) or Zn(s). This is also true for elements found in nature as diatomic (two-atom) elements
Explanation:
Answer: hot
Explanation:
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and the system will be cold and surroundings will be hot.
Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and the system will be hot and surroundings will be cold.
As heat is absorbed, the reaction is endothermic and the system will feel hot.
Ans: Elements in the same period have the same number of electron shells.
Answer:
4.68x10²⁵ ions of Na⁺
Explanation:
First of all, we dissociate the salt:
NaCl(aq) → Na⁺(aq) + Cl⁻(aq)
An aqueous solution of NaCl dissociates in chlorides anions and sodium cations. Ratio is 1:1, per 1 mol of NaCl, we have 1 mol of Na⁺
We determine the moles of salt: 4543.3 g . 1mol / 58.45 g = 77.7 moles
77.7 moles are the amount of NaCl, therefore we have 77.7 moles of Na⁺.
We count the ions:
1 mol fo Na⁺ has 6.02x10²³ ions
77.7 moles of Na⁺ must have (77.7 . 6.02x10²³) / 1 = 4.68x10²⁵ ions of Na⁺
Answer:
51207 torr is the new pressure of the gas
Explanation:
We can solve this question using combined gas law that states:
P1V1T2 = P2V2T1
<em>Where P is pressure, V volume and T absolute temperature of 1, initial state and 2, final state of the gas</em>
<em> </em>
Computing the values of the problem:
P1 = 710torr
V1 = 5.0x10²mL
T1 = 273.15 + 30°C = 303.15K
P2 = ?
V2 = 25mL
T2 = 273.15 + 820°C = 1093.15K
Replacing:
710torr*5.0x10²mL*1093.15K = P2*25mL*303.15K
3.881x10⁸torr*mL*K = P2 * 7.579x10³mL*K
P2 = 51207 torr is the new pressure of the gas
