Answer:
The percent by mass of water in this crystal is:
Explanation:
This exercise can be easily solved using a simple rule of three where the initial weight of the hydrated crystal (6,235 g) is taken into account as 100% of the mass, and the percentage to which the mass of 4.90 g corresponds (after getting warm). First, the values and unknown variable are established:
- 6,235 g = 100%
- 4.90 g = X
And the value of the variable X is found:
- X = (4.90 g * 100%) / 6,235 g
- X = approximately 78.6%.
The calculated value is not yet the percentage of the water, since the water after heating the glass has evaporated, therefore, the remaining percentage must be taken, which can be calculated by subtraction:
- Water percentage = Total percentage - Percentage after heating.
- <u>Water percentage = 100% - 78.6% = 21.4%</u>
No, because the sun stays in the same exact place all of the time
Answer: The image from the question has the correct answers.
Explanation:
As summarized in the attached table.
Three classes: 28×3=84 students
8 test tubes per student: 84× 8= 672
hope this helps!
Answer:
Explanation:
There are three types of interactions involved between the particles when solution are formed.
1 : Solute - solute interaction:
2 : Solute - solvent interaction:
3 : Solvent - solvent interaction:
1 : Solute - solute interaction:
It is the inter-molecular attraction between the solute particles.
2 : Solute - solvent interaction:
It involve the inter-molecular attraction between solvent and solute particles.
3 : Solvent - solvent interaction:
It involve the intermolecular attraction between solvent particles.
Solutions are formed if the intermolecular attraction between solute particles are similar to the attraction between solvent particles.
Exothermic process:
The process will exothermic when solute solvent bonds are formed with the release of energy and energy required to brake the solute-solute particles and solvent solvent particles are less.
Endothermic process:
The process will be endothermic when energy required to break the solute-solute particles and solvent solvent particles are higher than energy released when solute solvent bonds are formed .
