Scientists use carbon-14 to date ancient fossils.
Plants and animals absorb carbon-14 produced by cosmic rays. The ratio of C-14 to C-12 is constant when they are alive.
When they die, the C-14 decays to C-12, and the ratio changes.
Carbon-14 has a half-life of 5730 years. Thus, the object loses half its C-14 every 5730 years.
Scientists can use the C-14 to C-12 ratio to date fossils up to 70 000 years old.
The answer for the fourth question is Sr and F.
Electron domain geometry takes into account the bonds and the free electrons around the atom to predict the geometry.
A tigonal planar geometry means that all the electron domains are in the plane and that they are as far away as they can. That means that there are three electron domains in the plane separated at 120 ° each other.
sp2 means that there are three hybrid electron domains, and the geometrh that leads to the minimal repulsion force is they placed at 120°, which exactly the trigonal planar geometry described up.
Then the answer is sp2
You can check in your book, that sp corresponds to two domains, located linearly, at 180°; and sp3 is four domains with the form of tetrahedral with 109.5° angles.
Answer:
I.A thiol containing reagent and Heating(gentle)
II. Disulfide bond Breaker for Keratin
III. curling the hair physically
IV.A good oxidizing agent application
V. Disulfide bonds reformer for keratin to hold the shape
Explanation:
The hair is mostly made of Keratin which is a structural proteins with about 15% cysteine
In order to change the hair appearance on the outside a reducing agent is required containing a thiol as to reduce the formation of the sulfide and disulfide bridges formation in the hair so the that any changes can be applied without the body naturally turning it back, i-e allowing easier manipulation after this hairs are to be curled physically in order to keep this a oxidizing agent is applied and then finally a keratin reformer is added to hold the shape
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