Answer:
180 mg
Explanation:
For a first-order reaction, we can calculate the amount of aspirine (A) at a certain time (t) using the following expression.

where,
k: rate constant
A₀: initial amount
If we know the half-life (
) we can calculate the rate constant.

When t = 4 h and A₀ = 400 mg, A is:

The values for hydroxide ions, hydronium ions and pH are found in the attached picture.
Explanation:
See the attached picture.
Learn more about:
pH
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Biotic and abiotic factors are the environmental conditions that the organisms have to face to live in a specified environment.
-Abiotic factors-
Abiotic factors are the physical and chemical conditions of an environment. For example : heat, salinity, pressure, light, wind, pH ...
-Biotic factors-
Biotic factors are all the biological conditions of an environment for a specie/taxa. It can include prey and predator abundance, available food amount, available space, intra and interspecific competition...
The development of organims is under the control of abiotic factors. Some are adapted to heat, cold etc ... The abiotic factors will define which organisms are able or not to live in a specified place.
The living organisms will constitute the biotic factors, which define if and how can an organism live in a specified environment.
So, the abiotic factors are controling the biotic factors of an environment.
Hope it helps you !
Answer :
During diffusion, when the concentration of the molecules on both sides of the membrane is the same, the molecules will continue to move across the membrane in both the direction.
Answer 3 : It allows single-celled organism to reproduce, and other organism to repair damage tissues and grow.
Answer 4: The nucleus is an organelle that is surrounded by the cytoplasm, a jelly-like fluid.
Explanation :
Diffusion : It is a process where liquid moves from higher concentration to the lower concentration through permeable membrane.
When the concentration of the molecules on both sides of the membrane is same and the membrane is permeable membrane then diffusion will occur and the molecules will moves continuously across the membrane in both the direction.
Answer 3 :
Mitosis : It is a process of cell division. In this process, nucleus divides into two daughter cell and each daughter cell contains same number of chromosomes as present in parent nucleus.
The main purpose of the mitosis is to repair damaged tissues and growth.
Answer 4 :
Nucleus is a type of cell organelle. It is present in both animal and plant cells and it is the brain of the cell. It is present only in eukaryotic cell.
Nucleus is an organelle which is surrounded by the cell membrane which protects its from the other cells.
Cytoplasm is a jelly-like fluid which is present in the cell membrane which is made up of salt and water.