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30. Which of the following compounds contains the highest percentage of Nitrogen? [tex]\[ N = 14 \][/tex]

A. [tex]\( NH_3 = 17.0 \)[/tex]
B. [tex]\( NH_4Cl = 53.5 \)[/tex]
C. [tex]\( NH_4NO_3 = 80.0 \)[/tex]
D. [tex]\( (NH_4)_2SO_4 = 132.0 \)[/tex]

31. Which of the solutions below could act as a self-indicator in redox titration?

A. Methyl orange
B. Phenolphthalein
C. Potassium tetraoxomanganate (VII)
D. Sodium thiosulphate

32. The formula of Silver(I) oxide is

A. AgO
B. [tex]\( Ag_2O \)[/tex]
C. [tex]\( AgO_2 \)[/tex]
D. [tex]\( AgO_3 \)[/tex]

33. The compound formed between [tex]\(_{14}X\)[/tex] and [tex]\(_{16}Y\)[/tex] is

36. Water boils at a relatively high temperature because of the presence of:

A. Hydrogen bond
B. Metallic bond
C. Ionic bond
D. Covalent bond

37. How many atoms are contained in 0.2 moles of nitrogen? [tex]\[ N_A = 6.02 \times 10^{23} \][/tex]

A. [tex]\( 1.20 \times 10^{23} \)[/tex]
B. [tex]\( 3.62 \times 10^{23} \)[/tex]
C. [tex]\( 2.41 \times 10^{23} \)[/tex]
D. [tex]\( 4.82 \times 10^{23} \)[/tex]

38. Which of the following properties of covalent bonds is not correct? They:

A. Are mostly gases and volatile liquids
B. Are non-electrolytes
C. Have high boiling points
D. Have low boiling points

39. The formation of an electrovalent bond involves:

A. Cannot be recharged
B. Uses semi-solid electrolytes
C. Ionic force
D. Van der Waals' force
E. Is small in size
F. Is reversible


Sagot :

Sure, let's go through the solution step-by-step based on the given scenario to clarify any doubts:

Given Problem:

A computer lab initially has 9 computers. Each day, 5 additional computers are added to the lab. We need to determine the cumulative number of computers added over the span of 4 days and the total number of computers in the lab at the end of this period.

Steps to Solution:

1. Identify Initial Number of Computers:
- Initially, the lab has 9 computers.

2. Determine the Number of Days Computers are Added:
- The time span considered here is 4 days (from Monday to Thursday).

3. Computers Added Each Day:
- Every day, 5 new computers are added to the lab.

4. Calculate the Total Number of Computers Added Over the 4 Days:
- If 5 computers are added each day, then over 4 days, the total number added is [tex]\(5 \text{ computers/day} \times 4 \text{ days} = 20 \text{ computers}\)[/tex].

5. Determine the Total Number of Computers in the Lab After 4 Days:
- Initially, there were 9 computers. After adding 20 more computers over 4 days, the new total will be:
[tex]\[ \text{Initial computers} + \text{Computers added} = 9 + 20 = 29 \][/tex]

By following these steps, we can determine that:
- The cumulative number of computers added over 4 days is 20.
- The total number of computers in the lab at the end of the 4 days is 29.

Thus, the solution to the problem gives us:
- [tex]\( \text{Cumulative computers added} = 20 \)[/tex]
- [tex]\( \text{Total computers in the lab} = 29 \)[/tex]

If you have any more questions or need further explanation on specific steps, feel free to ask!