I would say that descriptive investigations aren't repeatable because it means that you are only describing something - you ask certain question about something, but do not form a hypothesis at that point yet. So it would be a waste of time to simply ask the same questions over and over again with no hypothesis to prove, which is why these types of investigations cannot be repeated.
The base of the garden in the scale drawing is 30 centimeters. (because 10x3 equals to 30)
The height of the garden in the scale drawing is 12 centimeters. (because 4x3 equals to 12)
The length of the patio in the scale drawing is 24 centimeters. (because 8x3 equals to 24)
The width of the patio in the scale drawing is 12 centimeters. (because 4x3 equals to 12)
<span>Spontaneous reactions need to be discovered first. Also, if reagents are transferred to the other cups used in the tests, it could contaminate them, leading to different colors being seen and the test results being invalid. Doing the reagent tests last ensure that the cups and reagents are only used on the substances that they are intended to.</span>
Answer:
<h2> 162g/mol</h2>
Explanation:
The question is incomplete. The complete question includes the information to find the empirical formula of nicotine:
<em>Nicotine has the formula </em>
<em> . To determine its composition, a sample is burned in excess oxygen, producing the following results:</em>
<em>Assume that all the atoms in nicotine are present as products </em>
<h2>Solution</h2>
To find the empirical formula you need to find the moles of C, H, and N in each of the compound.
- 1.0 mol of CO₂ has 1.0 mol of C
- 0.70 mol of H₂O has 1.4 mol of H
- 0.20 mol of NO₂ has 0.20 mol of N
Thus, the ratio of moles is:
Divide all by the smallest number: 0.20
Hence, the empirical formula is C₅H₇N
Find the mass of 1 mole of units of the empirical formula:
Total mass = 60g + 7g + 14g = 81g
Two moles of units of the empirical formula weighs 2 × 81g = 162g and three units weighs 3 × 81g = 243 g.
Thus, since the molar mass is between 150 and 180 g/mol, the correct molar mass is 162g/mol and the molecular formula is twice the empirical formula: C₁₀H₁₄N₂.
Answer:
Following are the solution to this question:
Explanation:
The octapeptides are: 
Its structure includes free glycine amino, and alanine residues free carboxylic. Its peptides are customarily extracted from the left side free NH2 residues as well as the right side free -COOH residues only in the same direction, the sequence is provided.
please find the structure in the attached file.