Carbon -14 and Carbon 12 are the two substances geologists use in radiocarbon dating.
Answer: Option B
<u>Explanation:
</u>
Radiocarbon dating denotes the determination process of the age of fossils of plants or animals based on the ratio of carbon atoms 14 to 12. Carbon naturally exists in two non-radioactive isotopes, Carbon-12 and Carbon-13 and one radioactive isotope carbon 14. The carbon 14 gets released on continuous cosmic reaction with atmospheric nitrogen.
These carbon 14 will be absorbed by the living plants and from the plants. Then, it will enter inside the animals which consume the plants. But once the plants and animals died, they ceased to intake carbon-14. In their living state, the ratios of carbon atoms 14 to 12 in them tends to similar to the ratio in atmosphere.
But after they die, the ratio of C-14 to C-12 will be varying from the ratio of C-14 to C-12 in atmosphere as the concentration of C-14 will be decreasing in the dead animals and plants. Thus using this ratio, geologists can find the fossil's age.
The atomic number(Z) is equal to the number of protons to equal to number of electrons.
The number of neutrons is equal to atomic mass minus the atomic number
n=A-Z
For Zn^2+, Z=28, e=28
For iron, Z=25,A=55
The number of neutrons is 55-25=30
The charge is zero
For O^2-, Z=8+2=10, n=p=10
The number of neutrons is 16-10=6
For sulfur, Z=16,A=34
For S2-, Z=16+2=18, A=34
The charge is 2-
- The atomic number is the basis of the periodic table.
- It is equal to the number of protons.
- The number of neutrons is atomic mass minus atomic number.
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Answer:
138 mg
Explanation:
A company is testing drinking water and wants to ensure that Ca content is below 155 ppm (= 155 mg/kg), that is, <em>155 milligrams of calcium per kilogram of drinking water</em>. We need to find the maximum amount of calcium in 890 g of drinking water.
Step 1: Convert the mass of drinking water to kilograms.
We will use the relation 1 kg = 1000 g.

Step 2: Calculate the maximum amount of calcium in 0.890 kg of drinking water

Matematically speaking, maybe because:
The number of substances = number of elements + number of different combinations of those elements
So, the answer to 27.) would be <em>2x.</em> Both 6x and 2x can be divided by 2x, but they can't go any higher without the end-answer becoming a fraction. As such, 2x is the greatest common factor.
For 28.), x and x^2 can't be like terms, since like terms have the same variable and exponent :)
Hope I could help!