I found the rest of the exercise on the internet and these are the options.
"-Undifferentiated vertebrae throughout the body.
-One neck vertebra allowing up and down movement.
-Many neck vertebrae that allow for greater mobility.
<span>-Two neck vertebrae allowing up and down and sideways movement."
The correct answer would be the third. - "</span>Many neck vertebrae that allow for greater mobility." The <span>present-day organism with four limbs has a neck with several vertebrae that allow movements of rotation (mostly because of only two vertebrae at the top of the neck), and side way movements, as well as back and forth movements.</span>
Answer:
0.56 g
Explanation:
<em>A chemist determines by measurements that 0.020 moles of nitrogen gas participate in a chemical reaction. Calculate the mass of nitrogen gas that participates.</em>
Step 1: Given data
Moles of nitrogen gas (n): 0.020 mol
Step 2: Calculate the molar mass (M) of nitrogen gas
Molecular nitrogen is a gas formed by diatomic molecules, whose chemical formula is N₂. Its molar mass is:
M(N₂) = 2 × M(N) = 2 × 14.01 g/mol = 28.02 g/mol
Step 3: Calculate the mass (m) corresponding to 0 0.020 moles of nitrogen gas
We will use the following expression.
m = n × M
m = 0.020 mol × 28.02 g/mol
m = 0.56 g
Answer:
9.00
Explanation:
Data:
[H⁺] = 1.0 × 10⁻⁹ mol·L⁻¹
Calculation:
pH = -log[H⁺] = -log(1.0 × 10⁻⁹) = -log(1.0) - log(10⁻⁹) = -0.00 - (-9) = -0.00 + 9 = 9.00
I think the correct answer is the first option. It has nonpolar bonds and a symmetrical structure. The structure of a BF3 molecule shows a symmetrical trigonal geometry. The net dipole moment of the molecule is zero therefore it is polar.
