dinosaur footprint
Explanation:
A dinosaur footprint is an example of a trace fossil. A trace fossil is a type of fossil that shows the activities of organisms that lived in the past.
- Fossils are the preserved remains of organisms that lived several years ago.
- Fossils are usually found in sedimentary rocks and thick layers of ice in temperate and polar regions.
- Body fossils are the remains of the body parts of an organism that has been preserved. They can be skeletal parts, teeth, eggs e.t.c
- A trace fossil shows the preserved remains of the activities of an organism.
- They can be fingerprints, burrows and borings, feccal pellets e.t.c
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Answer:
You determine the weighted averages if the individual isotopic masses.
Procedure:
The atomic mass of Si is the <em>weighted average </em>of the atomic masses of its isotopes.
We multiply the atomic mass of each isotope by a number representing its relative importance (i.e., its percent abundance).
The three stable isotopes of Si are Si-28 (27.98 u, 92.22 %), Si-29 (28.98 u, 4.69 %), and Si-30 (29.97 u, 3.09 %).
Set up a table for easy calculation.
0.9222 × 27.89 u = <em>x</em> u
0.0469 × 28.98 u = <em>y</em> u
0.0309 × 29.97 u = <em>z</em> u
TOTAL = (<em>x</em>+<em>y</em>+<em>z</em>) u = atomic mass of Si.
Answer:
Dipole-dipole attractions
Explanation:
PBr₃ is a <em>trigonal pyramidal</em> molecule.
The P-Br bonds are polar, with their bond dipoles pointing toward the Br atoms (see below).
The x-components of the dipoles cancel, but the y-components reinforce each other.
The partially negative Br atoms are attracted to the partially positive N atoms in neighboring molecules.
These dipole-dipole forces are the strongest intermolecular forces in PBr₃.
Answer:
The highest point on a wave is the Crest_, while the lowest point is the Trough Get a ruler and measure the wavelength and amplitude of the above wave. (a) Waves P and Q have the same frequency, but wave P has twice the What type of wave is produced when you move one end of a horizontal spring up
Explanation: