The three states of matter are solid, liquid and gas phase. The solid has a more definite shape and volume. The particles are locked into place. It cannot be further compressed due to the bond that exists between the molecules. The kinetic energy of the molecules is close to none because the molecules are so close and so compact with each other. For liquids, it has a medium shape and volume. The particles can move or slide past each other due to the small space available for movement. It cannot be compressed further due to the repulsive forces that acts between them. The kinetic energy is medium. For gases, it has no shape and volume because the particles can move freely from one other. Their collisions are rare due to the distance between them. The kinetic energy of the molecules is high because there is room for movement. It can be compressed easily.
When dynamite explodes, it releases a large amount of light and heat. This is an example of _____.
slow combustion
rapid combustion
an exothermic reaction
an endothermic reaction
a chemical change
a physical change
Answer
Rapid Combustion
Explanation:
An explosion is a combustion and a quick reaction, That makes it rapid
Answer:
0.22 grams of magnesium
This seems too low, so check the calculations/
Explanation:
How is the heat delivered? Is the magnesium hot and added to the water? If so, at what temperature.
Is the heat generated from an exothermic chemical reaction?
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I'll assume here that the heat comes from the reaction of magnesium with water. The balanced equation is:
Mg + 2H2O = Mg(OH)2 + H2
It has a heat of reaction of −924.7 kJ/mol.
We need enough Mg to heat 30 ml of water from 22°C to 90°C. The specific heat of water is needed. It is 4.184 J/g-K. It tells us that 4.184 Joules are needed to raise the temperature of water by 1 degree K.
30 ml of water with density 1 gram/ml means we have 30 grams of water. (We'll ignore the water that is added from the chemical reaction.).
Lets calculate the Joules required to raise 30 grams of water from 22°C to 90°C. Note that the specific heat has units of g and Kelvin. Since we need a temperature change, the number value for ΔT is the same for both °C and °K. So the temperature change is +68°K.
We can now calculate the Joules required:
(30 grams H2O)*(4.184 J/g-K)*(+68°K) = 8535.4 Joules or 8.5 kJ to 2 sig figs.
The Mg/H2O heat of reaction of −924.7 kJ/mol. will allow us to calculate the amount of Mg needed to supply 8.5 kJ. The minus sign tells us that the reaction RELEASES energy (the energy leaves the "system" of Mg and H2O).
Calculate the moles of Mg needed to release 8.5 kJ:
(924.7 kJ/mole)*(x moles) = 8.5 kJ
x moles = 0.0092 moles
Whoa. That is only (0.0092 moles)*(24.03 g/mole) = 0.22 grams of magnesium
This seems low to me, so check on the heat of reaction figure I used. And don't let the hydrogen get away.
The bottle left outside will have the same vapor pressure as the bottle inside the room because they both contain water.
The bottle left outside will have higher vapor pressure than the bottle from the room.
No change to either bottle.
The protons are located inside the nucleus and have a positive charge.
The electrons are located outside the nucleus and have a negative charge.
The neutrons are located inside the nucleus and have no charge.
Explanation:
Learn more about subatomic particles here:
Answer:
1-There Must be some displacement in the direction of force. 2-Angle between force and displacement is 0°.
In a laboratory synthesis, a student begins with 2.90 mL of acetic anhydride (density=1.08gml−1) and 1.23 g of salicylic acid. Once the reaction is complete, the student collects 1.24 g of aspirin.
1. Determine the theoretical yield of aspirin for the reaction. Express your answer using three significant figures.
2. Determine the percent yield of aspirin for the reaction. Express your answer using three significant figures.
Answer:
1.- Theoretical yield is 1.64 g of aspirin
2.- %Yield is 75.6%
Explanation:
The theoretical yield of aspirin could be calculated by the molar relation between anhydride acetic and salicylic acid which is 1:1. It means that the reaction of one mole of anhydride acetic with one mole of salicylic acid will produce 1 mole of aspirin and one mole of acetic acid.
It is possible to calculated the number of moles using moles=grams/molar mass. in the attached figure we can see the molar mass of each compound.
The number of moles of anhydride acetic can be calculated using the density and the volumen.
g=(1.08 g/mL)*(2.90 mL)=3.13 g of anhydride
moles= 3.13 g/(102.09 g/mol)= 0.031 moles of anhydride acetic
The same for salicylic acid and we have:
moles= 1.23g/ (138.12 g/mol)= 0.0090 moles of salicylic acid
There is not 1:1 relation between this two compounds because there is much more anhydride acetic than salicylic acid, so the reaction is limited by the 0.0090 moles of salicylic acid which produce 0.0090 moles of aspirin.
g= moles*molar mass
Theoretical yield of aspirin= (0.009 moles)*(182.13 g/mol)= 1.64 g
The percent yield of aspirin for the reaction can be calculated using the nex formula:
%yield= ((real yield)/(theoretical yield))*100
The real yield was 1.24 g of aspirin
%Yield=(1.24g/1.64)*100=75.6%
To determine the theoretical yield of aspirin, calculate the moles of acetic anhydride and salicylic acid, use the balanced equation to find the moles of aspirin, and convert to grams. The percent yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100.
To determine the theoretical yield of aspirin, we need to first calculate the number of moles of acetic anhydride and salicylic acid. Then, we use the balanced equation to find the number of moles of aspirin produced. Finally, we convert the moles of aspirin to grams using its molar mass. The percent yield is calculated by dividing the actual yield by the theoretical yield and multiplying by 100.
Step 1: Calculate the moles of acetic anhydride
2.90 mL × 1.08 g/mL = 3.132 g
Moles of acetic anhydride = mass / molar mass = 3.132 g / 102.09 g/mol = 0.0307 mol
Step 2: Calculate the moles of salicylic acid
Moles of salicylic acid = mass / molar mass = 1.23 g / 138.12 g/mol = 0.0089 mol
Step 3: Use the balanced equation to find the moles of aspirin produced
According to the balanced equation: 1 mol of acetic anhydride reacts with 1 mol of salicylic acid to produce 1 mol of aspirin
Since the moles of acetic anhydride and salicylic acid are the same, the moles of aspirin produced = 0.0089 mol
Step 4: Calculate the theoretical yield of aspirin in grams
The molar mass of aspirin is 180.16 g/mol
Theoretical yield of aspirin = moles of aspirin × molar mass of aspirin = 0.0089 mol × 180.16 g/mol = 1.61 g
Step 5: Calculate the percent yield of aspirin
Percent yield = (actual yield / theoretical yield) × 100
Percent yield = (1.24 g / 1.61 g) × 100 = 77.0%
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