Answer:
52 da
Step-by-step explanation:
Whenever a question asks you, "How long to reach a certain concentration?" or something similar, you must use the appropriate integrated rate law expression.
The i<em>ntegrated rate law for a first-order reaction </em>is
ln([A₀]/[A] ) = kt
Data:
[A]₀ = 750 mg
[A] = 68 mg
t_ ½ = 15 da
Step 1. Calculate the value of the rate constant.
t_½ = ln2/k Multiply each side by k
kt_½ = ln2 Divide each side by t_½
k = ln2/t_½
= ln2/15
= 0.0462 da⁻¹
Step 2. Calculate the time
ln(750/68) = 0.0462t
ln11.0 = 0.0462t
2.40 = 0.0462t Divide each side by 0.0462
t = 52 da
Answer: 1.
: oxidation reduction
2.
: precipitation
3.
: Double displacement
Explanation:
Oxidation-reduction reaction or redox reaction is defined as the reaction in which oxidation and reduction reactions occur simultaneously.
Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.

Double displacement reaction is defined as the reaction where exchange of ions takes place. Double displacement reaction in which one of the product remain in solid form are represented by (s) after their chemical formulas. Such double displacement reaction are called as precipitation reaction.

Double displacement reaction is defined as the reaction where exchange of ions takes place.

Single displacement reaction is defined as the reaction where more reactive element displaces a less reactive element from its chemical reaction.
Decomposition reaction is defined as the reaction where a single substance breaks down into two or more simpler substances.
Synthesis/Combination reaction is defined as the reaction where substances combine in their elemental state to form a single compound.
Answer:
An object has a negative charge if it's atoms have more electrons. On the other hand if an object had more protons, then it would have a positive charge.
Hope this helps!!
Answer:
Conduction is the transfer of thermal energy from one molecule to another within an object. Conduction also happens between two objects in direct contact if they have different temperatures. The hotter molecule vibrates because of the added heat. This vibration and movement transfer the energy to the surrounding molecules. The transfer of energy continues until all the molecules have the same temperature.
Conduction takes place in solids, liquids, and gases. However, it happens fastest in solids because the molecules in solids are closely packed.
A scientific law describes an observed occurrence or phenomena.