Answer:
There are five evidences that tell whether a chemical change has occurred. These are change of color, change of odor, change in temperature or energy, formation of gas and formation of a precipitate.
Explanation:
Chemical Change- This is a type of chemical reaction which occurs when the properties of one or more atoms change and results into a<u> newly formed substance. </u>
Let's have a further discussion of the evidences.
1. Change of Color- Color change is caused by the combination of two or more substance with different molecular structures. A popular example of this is the Statue of the Liberty, which is made of copper plates. Due to the exposure of copper to elements like water, it changed color.
2. Change of Odor- This can be best presented with rotting food. During the rotting process, the food undergoes a chemical reaction. The result is a rotten smell.
3. Change in Temperature or Energy- An example of this is the burning of wood. Its change is considered non-reversible.
4. Formation of Gas- This can be best presented with the cake batter (the one being used to make cakes or pancakes). The batter rises which means it is forming gas. This is caused by the reaction of the baking soda and the acid.
5. Formation of a Precipitate- This occurs when two soluble salts combine and their outcome is an insoluble salt (this is the precipitate).
Take note that if any of these evidences occur, then there's definitely a chemical reaction.
Answer:
Liquid to Gas
Explanation:
The particles need energy to rise and over come the attractions between them as the liquid gets warmer more particles have sufficient, energy to escape from liquid. eventually even particles in the middle of the liquid form bubbles of gas in the liquid At this point the liquid is boiliing and turning into gas.
Answer:
a) To determine the facilities that contribute the most to recycling check the pie chart and select the facility with the largest portion while to determine the facilities that contribute the least to recycling check the pie chart and select the facility with the smallest portion
b) Energy is saved because the products which are recycled usually require less energy to turn them into usable materials
c) It saves energy through recycling. It helps sustains the environment. It decrease the emission of green house gases
Explanation:
The question is not complete
a) Pie chart is the graphical representation of information in which the information is represented in a circle. The circle is divided into segments and the portion with the largest segment has the highest percentage.
To determine the facilities that contribute the most to recycling check the pie chart and select the facility with the largest portion while to determine the facilities that contribute the least to recycling check the pie chart and select the facility with the smallest portion
b) Extraction and processing of raw resources to make end products requires a lot of energy. With recycling energy is saved because the products which are recycled usually require less energy to turn them into usable materials
c) It saves energy through recycling. It helps sustains the environment. It decrease the emission of green house gases.
Answer: as the temperature increases, the kinetic energy of the molecules increases
Explanation: The kinetic energy of the molecules is the energy possessed by virtue of motion of the particles.
Kinetic energy of the particles is directly proportional to the temperature of the gas.
where T= temperature
R= gas constant
Thus if the temperature is increased, the molecules start moving more randomly and gain kinetic energy.
Answer: This chemical reaction is a neutralization reaction between the Milk of Magnesia and the HCl from the stomach. The balanced equation is Mg(OH)2 (s) + 2 HCl (aq) → MgCl2 (aq) + 2 H2O (l)
Explanation:
The reaction between the HCl and the Mg(OH)2 is a neutralizacion reaction , because the HCl is a strong acid and the Mg(OH)2 is a weak base, then both react and the pH of the medium will increase, so the stomach trouble will dissapear.
Mg(OH)2 (s) + 2 HCl (aq) → MgCl2 (aq) + 2 H2O (l)
Magnesium hydroxide is a weak base due to its very limited solubility in water. This property is a great advantage when treating the excess of HCl in the stomach, because the Mg(OH)2 molecule does not dissociated easily until it reacts with the hydrogen ion, H+ of the HCl. So the effect of the Mg(OH)2 will last longer until the annoyance dissapear.
