Answer:
-
419kJ/mol
- 5,0,0,+12
- That catches fire spontaneously
Explanation:
1. Topic: Chemistry
ElementFirst Ionization Energy (kJ/mol) Lithium520Sodium496Rubidium403Cesium376According to the above table, which is most likely to be the first ionization energy for potassium?
2. Topic: Chemistry, Atom
The correct set of four quantum numbers for the valence electrons of the rubidium atom (Z=37) is:
3. Rubidium and cesium are pyrophoric. Here the term pyrophoric means:
- That does not catch fire at all
- That catches fire spontaneously
Answer:
7.5 g
Explanation:
There is some info missing. I think this is the original question.
<em>Ammonium phosphate ((NH₄)₃PO₄) is an important ingredient in many fertilizers. It can be made by reacting phosphoric acid (H₃PO₄) with ammonia (NH₃). What mass of ammonium phosphate is produced by the reaction of 4.9 g of phosphoric acid? Be sure your answer has the correct number of significant digits.</em>
<em />
Step 1: Write the balanced equation
H₃PO₄ + 3 NH₃ ⇒ (NH₄)₃PO₄
Step 2: Calculate the moles corresponding to 4.9 g of phosphoric acid
The molar mass of phosphoric acid is 98.00 g/mol.

Step 3: Calculate the moles of ammonium phosphate produced from 0.050 moles of phosphoric acid
The molar ratio of H₃PO₄ to (NH₄)₃PO₄ is 1:1. The moles of (NH₄)₃PO₄ produced are 1/1 × 0.050 mol = 0.050 mol.
Step 4: Calculate the mass corresponding to 0.050 moles of ammonium phosphate
The molar mass of ammonium phosphate is 149.09 g/mol.

Answer:
2.44 K IS THE TEMPERATURE OF THE GAS
Explanation:
PV = nRT
P = 0.5 atm
V = 2 L
n = 5 moles
R = 0.082 L atm mol^-1 K^-1
T = ?
Substituting for T in the equation, we obtain:
T = P V / nR
T = 0.5 * 2 / 5 * 0.082
T = 1 / 0.41
T = 2.44 K
The temperature of the gas is 2.44 K
The reaction: 2H2(g) + O2(g) → 2H2O(g), can be interpreted as: a. 2 moles of hydrogen gas reacts with 1 mole of oxygen gas to produce 2 moles of water.
Answer:
What are the advantages of titration?
Titrimetric analysis commonly referred to as volumetric analysis offers distinct advantages over cumbersome gravimetric methods:
Speed of analysis.
Instantaneous completion of reactions.
Greater accuracy due to minimization of material loss involved in decanting, filtration, precipitation or similar operations.
Explanation:
Disadvantages
It is a destructive method often using up relatively large quantities of the substance being analysed.
It requires reactions to occur in a liquid phase, often the chemistry of interest will make this inappropriate.
It can produce significant amounts of chemical waste which has to be disposed of.
It has limited accuracy.
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