Using the radiocarbon dating technique and applying the decay formula, it is calculated that the age of the charcoal from the an ancient campsite is approximately 9,500 years.
The age of the charcoal can be found using the technique of radiocarbon dating, which capitalizes on the process of radioactive decay. The isotope carbon-14 (¹4C) is used in this method as it has a known half-life of 5730 years. The number of decays per minute per gram of carbon in a live organism is known as its activity.
Initially, the activity was given as 15 decays per minute per gram. The present activity of the carbon in the charcoal is provided at 1580 decays per minute for a 0.94 kg or 940 gram sample. Thus, the current activity per gram is 1580/940 equals approximately 1.68 decays per minute per gram.
Given that the half-life of ¹4C is 5730 years, we can apply the formula for calculating the time passed using the rate of decay, which is given as T = (t1/2 / ln(2)) * ln(N0/N), where 'ln' is the natural logarithm, 'N0' is the initial quantity (15 decays/minute per gram), 'N' is the remaining quantity (1.68 decays/minute per gram).
Plugging in the given values, we get T = (5730 / ln(2)) * ln(15/1.68), which gives us approximately 9,500 years. Therefore, the age of the charcoal is around 9,500 years.
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periodic poperties of elements in groups
and periods
atomic radius
ionization potential
B. a change in
c. not related to
D. only an increase in
Answer:
option B is correct
Explanation:
impulse is a change in momentum
b.. Different kinds of elements have different kinds of atoms.
c..The protons, neutrons and electrons are different for different kinds of atoms.
d... An atom always has the same number of protons and electrons.
e... An atom always has the same number of protons and neutrons.
f.... Atoms have no mass because they are very small.
Q2 .Compare the Rutherford's model and the Bohr's model of the atom. State one similarity and one difference between them.
Q3..what observation from rutherford's gold foil experiment made him conclude that an atom has a tiny but dense nucleus that is positively charged?
Q4.. Explain why the nucleus of an atom is positively charged, while the atom is electrically neutral.
Q5...The symbols and atomic numbers of three elements are as follows:
Ne Atomic number 10
A/ Atomic number 13
K Atomic number 19
a.. identify each element from its symbol.
b.. How many protons and electrons does an atom of each element have?
c.. Draw the electronic structure of the atom of each element.
Answer:
a. false
b. true
c. false
d. false
e. false
f. false
Q2: Both have electrons orbiting around the nucleus; Bohr's model is more detailed and expands on Rutherford's
Q5:
a.
Ne = neon
Al = aluminum
K = potassium
b.
Ne = 10 electrons/protons
Al = 13 electrons/protons
K = 19 electrons/protons
Answer:
2Ag⁺ (aq) + CrO₄⁻² (aq) ⇄ Ag₂CrO₄ (s) ↓
Ksp = [2s]² . [s] → 4s³
Explanation:
Ag₂CrO₄ → 2Ag⁺ + CrO₄⁻²
Chromate silver is a ionic salt that can be dissociated. When we have a mixture of both ions, we can produce the salt which is a precipitated.
2Ag⁺ (aq) + CrO₄⁻² (aq) ⇄ Ag₂CrO₄ (s) ↓ Ksp
That's the expression for the precipitation equilibrium.
To determine the solubility product expression, we work with the Ksp
Ag₂CrO₄ (s) ⇄ 2Ag⁺ (aq) + CrO₄⁻² (aq) Ksp
2 s s
Look the stoichiometry is 1:2, between the salt and the silver.
Ksp = [2s]² . [s] → 4s³
Onoble gases
O halogens
O transitional metals
Group/Family 18 on the periodic table is called the noble gases.
Group/Family 18 on the periodic table is called the noble gases. The noble gases are a group of chemical elements that have full valence electron shells, which makes them stable and nonreactive. This group includes elements like helium, neon, argon, krypton, xenon, and radon.
B. NH3 < PH3< CH4
C. CH4 < PH3 < NH3
D. NH3 < CH4< PH3
E. PH3< NH3 < CH4
Answer:
B. NH3 < PH3< CH4
Explanation:
Hello,
In this case, taking into account that the boiling point of ammonia, methane and phosphorous trihydrate are -33.34 °C, -161.5 °C and -87.7 °C, clearly, methane has the lowest boiling point (most negative) and ammonia the greatest boiling point (least negative), therefore, ranking is:
B. NH3 < PH3< CH4
Best regards.