Answer: 1.25 grams of Potassium-40
Explanation: When the amount of a compound is consumed by half, the time passed is called "the half life". This term is particularly important in nuclear chemistry. Potassium-40 is an isotope of potassium element and it is radioactive. As a result, the consumption time of this radioactive isotope is valuable information since radioactive isotopes are detrimental to health and nature.
For example, in this question, within 1.3 billion years, half amount of the potassium-40 disappears. 2.6 billion years ago, there were 5 grams of potassium-40 and when 1.3 billion years pass, half of the 5 grams of potassium-40 will disappear and there will will be 2.5 grams of potassium-40 left (5 grams of potassium-5 grams of potassium*(1/2)[half amount]=2.5 grams of potassium-40 left). As a result, 2.5 grams of potassium-40 is the amount that is present 1.3 billion years ago (2.6 billion years-1.3 billion years [half-life]=1.3 billion years). There will be 1.3 billion years left until today, so we still have to calculate the amount disappeared in 1.3 billion years. Thus, half of the 2.5 grams must disappear in 1.3 billion years left (2.5 grams - 2.5 grams*(1/2)[half amount]=1.25 grams). Finally, we have 1.25 grams of potassium-40 left since 2.6 billion years ago.
Le Chatelier's principle states that when a change is brought to a system in equilibrium, the equilibrium will shift in a manner to reverse that change.
If the pressure is increased, the system will try to reduce the pressure. The only way it can do this is by producing less gas. Therefore, shifting the equilibrium to the left. Thus, the statement is true.
However, some common household products, including drain and toilet bowl cleaners and some dishwasher detergents, contain damaging caustic substances, such as sodium hydroxide and sulfuric acid. Caustic substances (strong acids and alkalis), when swallowed, can burn the tongue, mouth, esophagus, and stomach.
Analogous structures are those structures in different species which perform the same function, have similar appearance and structure but are not evolved together; therefore do not share a common ancestor. Homologous and analogous organs video explains in a simple way.
Hello,
In metallic bonds, the valence electrons from the s and p orbitals of the interacting metal atoms delocalize. That is to say, instead of orbiting their respective metal atoms, they form a “sea” of electrons that surrounds the positively charged atomic nuclei of the interacting metal ions.
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