Which fraction of a Sr-20 sample remains unchanged after 87.3 years?
Answers
More importantly, the half life of strontium must be given.
For demonstration sake, let us assume Sr-85 is the isotope. It has a half-life of 64.853 days and I'm assuming the units of 87.3 is in days.
A/Ao = e^-(ln2/t)T
where A- final amount Ao -initial amount t- halflife T-total time elapsed
% = e^-(ln2/64.853)(87.3) = 0.3933 or 39.33%
Related Questions
What element is this? How do you know?
Unknown element X combines with oxygen to form the compound XO2. If 44.0 grams of element X combines with 8.00 grams of oxygen, what is the atomic mass of element X?A. 16 amu B. 44 amu C. 88 amu D. 176 amu E. 352 amu
Cranberries and grapes may have therapeutic value. A cranberry company obtained the patent for a process to extract the oil from cranberry seeds. According to the patent, this oil can be used to treat breast cancer or to reduce its incidence. The oil can be used in drinks and foods. A grape juice company claims to have evidence that certain grapes have health benefits ranging from improving cardiovascular health to improving cognitive brain function in the elderly. These claims will be tested by the Food and Drug Administration (FDA) before the companies are allowed to market their products for “treating” ailments or “improving” health. Until then, the companies can describe that their products “help to maintain” or “support” health. Until studies support their claims, the companies cannot ascribe direct health benefits to their products.Why would the FDA perform tests when a cranberry company and a grape company have already conducted research on the same products?A. The FDA is the only organization that can test if health actually improves.B. Tests that are performed by any company which benefits financially are considered unreliable.C. The FDA tests give reliability to the results of improved health obtained by each company.D. Tests performed by the FDA follow established scientific methods, but those performed by companies do not.
A solution of h2so4(aq) with a molal concentration of 6.80 has a density of 1.318 g/ml. what is the molar concentration of this solution?
Answers
Answers
Answer:
76.3 g of 1 mole of element Z
Explanation:
According to Avogadro’s number the number of particles in 1 mole of a substance is 6.023 x 10²³.
The mass of 3 x 10²³ particles is 38g
Therefore, the mass of 6.023 x 10²³ is = 76.3 g
x b). 8.3 x 10^3 kPa
c). 2.07 x 10^3 kPa
d). 2.07 x 10^4 kPa
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Answer:
A) 1.04 x 10^4 kPa
Explanation:
I'm not exactly sure how but I took the test and this was the correct answer. My calculations said it was B as well but I guess not...
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PV = nRT
where P - pressure 1.46 atm x 101 325 Pa/atm = 147 934.5 Pa
V - volume
n - number of moles - 1 mol
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature - 270 K
substituting these values in the equation
147 934.5 Pa x V = 1 mol x 8.314 Jmol⁻¹K⁻¹ x 270 K
V = 15.17 L
the volume is 15.17 L
Answers
Answer:
Buffers.
Explanation:
Hello,
When the body experiences acidic conditions, buffers such as phosphates in form of sodium-based phosphates and bicarbonates are produced by itself in order to stabilize the inner pH. Such buffers are majorly produced in the blood.
Best regards.
Final answer:
To neutralize acidic conditions, the body produces buffers, such as bicarbonate ions, which combine with hydrogen ions to regulate blood pH, maintaining it at around 7.4 for proper physiological function.
Explanation:
The human body produces substances known as buffers to neutralize acidic conditions and maintain homeostasis. These buffers include a combination of carbonic acid (H₂CO₃), bicarbonate ions (HCO₃⁻), and carbon dioxide (CO₂). When there's a decrease in blood pH, indicating acidity, bicarbonate ions can bind to free hydrogen ions, forming carbonic acid, which can then be converted to CO₂ and exhaled through the lungs, thereby reducing acidity.
If the blood becomes too alkaline, carbonic acid can release hydrogen ions, lowering pH. Furthermore, the kidneys regulate blood pH by excreting excess hydrogen ions and reabsorbing bicarbonate. An example of this regulation is when lactic acid, produced in our muscles during exercise, is neutralized by bicarbonate ions, forming carbonic acid that breaks down into CO₂ and water.
Learn more about Buffers here:
#SP3
Answers
Fluidity is the physical property that enables a substance to flow. Fluidity also refers to the state of being fluid. So basically, solid molecules has no fluidity. It is also believed that the fluidity of water increases as the water gets warmer.