Answer:
How many grams of H2 can be produced from the reaction of 11.5 grams of sodium with an excess of water? Hint: 2Na + 2H2O ---> 2NaOH + H2. Ans: 0.505g .
Explanation:
Answer: This option is incorrect: <span>B. Covalent compounds are held together by much stronger interparticle forces than are ionic compounds.
Justification:
Ionic bonds, held by ionic compounds, are much stronger than covalent bonds, held by covalent compounds.
In ionic bonds one element yields one or more electrons forming a cation (a positively charged ion) and the other element accepts the electrons forming an anion (a negatively charged ion).
The anion and the cation are electrostatically atracted by each other. This electrostatic atraction force, named ionic bond, is very strong.
As result of this, the ionic compounds form strong crystals with high boiling and fusion points. A good example of this the sodium chloride, formed by the union of cation Na(+) and anion Cl(-).
The covalent bonds are result of sharing electrons and do not form ions. This bond is weaker than the ionic bond.
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Answer:
1. Which statement correctly describes the classification of chemical reactions into different categories?
-Not all reactions fit into a category, and some reactions can fit into more than one category.
2. In a synthesis reaction, two atoms of sodium (Na) combine with one molecule of chlorine gas (Cl2) to produce sodium chloride (NaCl). How many molecules of sodium chloride are produced?
-Two
3. In the decomposition of water, why is twice as much hydrogen as oxygen formed?
- There are two atoms of hydrogen and one atom of oxygen in a water molecule.
4. Which component is transferred between substances in an oxygen-reduction reaction?
-Electrons
5. In a chemical reaction, substance A transfers electrons to substance B. Which statement is correct?
-Substance B is reduced and acts as the oxidizing agent.
Answer:
15.95
Explanation:
This question is a modification of the calculation of the empirical formula of a compound given its percent composition and atomic weights of the elements in the compound.
Here we are given the formula and the percent composition, so we know that there are 4 atoms of E per 2 atoms of N so lets solve using the information given.
In 100 grams of the binary compound we have
30.46 g N
69.54 g E
The number of moles is the mass divided by atomic weight:
mol N = 30.46 g / A.W N = 30.46 g / 14.00 g/mol = 2.18 mol N
mol E = 65.54 g / A.W E
Thus,
4 mol E/ 2 mol N = ( 69.54 g/ A.W E ) / 2.18
2 A.E = 65.54 g / 2.18 ⇒ A.W E = 69.54 g / ( 2 x 2.18 ) = 15.94 g
So the A.W is 15.94 g/mol which is close the atomic weight of O.
