Q1)
the number of moles can be calculated as follows
number of moles = mass present / molar mass
number of moles is the amount of substance.
4.8 g of Ca was added therefore mass present of Ca is 4.8 g
molar mass of Ca is 40 g/mol
molar mass is the mass of 1 mol of Ca
therefore if we substitute these values in the equation
number of moles of Ca = 4.8 g / 40 g/mol = 0.12 mol
0.12 mol of Ca is present
q2)
next we are asked to calculate the number of moles of water present
again we can use the same equation to find the number of moles of water
number of moles = mass present / molar mass
3.6 g of water is present
sum of the products of the molar masses of the individual elements by the number of atoms
H - 1 g/mol and O - 16 g/mol
molar mass of water = (1 g/mol x 2 ) + 16 g/mol = 18 g/mol
molar mass of H₂O is 18 g/mol
therefore number of moles of water = 3.6 g / 18 g/mol = 0.2 mol
0.2 mol of water is present
Answer:
By decreasing pressure.
Explanation:
In order to prevent balloons from popping while making sculptures, it is suggested to decrease the pressure of air in parent balloon. Decreasing the pressure of parent balloon will allow it to twist easily and make designs.
This strategy will work according to Boyle's Law which states that, "Pressure and Volume are inversely proportional to each other at constant temperature".
Mathematically,
P ∝ 1/V
Or,
P = k/V
Or,
PV = k
Hence, as the new designs made after twisting are of less volume, therefore it is good to decrease the pressure in advance otherwise the resulting less volume will increase the pressure of daughter small balloons and will explode them.
The Options are as follow,
<span> (1) CaCl</span>₂<span> (s) (3) CH</span>₃<span>OH (l)</span>
<span> (2) C</span>₂<span>H</span>₆<span> (g) (4) Cal</span>₂<span> (aq)</span>
Answer:
Option-1 is the correct answer.
Explanation:
As we know crystal formation is the property of solids. Therefore, in given options we are given with four different states of matter.
Option A, CaCl₂ is in a solid state , so it can exist in crystal form.
Option 2, C₂H₆ (Ethane) is in gas form, so it cannot form crystals.
Option 3, CH₃OH (Methanol) is present in liquid form, so it fails to form crystals.
Option 4, CaI₂, it is dissolved in water, Hence, it is in aqueous state, Therefore it also lacks crystal structure.
Answer:
Independent Variable: Grade Level
Dependent Variable: Growth in height
Hypothesis: Students in [Insert the grade level you believe will grow the quickest here] will experience the quickest growth in height.
Explanation:
Independent variables are the factors in which you manipulate to gain your results, in this case you would be changing the grade level you would observe to see the height.
Dependent variables are the factors that respond to changes in the independent variables. You don't control these events, you simply observe them. In this case, you merely observe the growth in height in accordance to the different grade levels you observe.
For the hypothesis, you would create your own hypothesis based on a guess you have. You create a hypothesis not based on the data, but on what you believe will be correct before doing the experiment. It doesn't have to be the correct answer, but just your thoughts.
Answer:
See explanation below
Explanation:
In this case we have the starting reactant which is the ethine, In the first step reacts with NaNH₂, a strong base. This base will substract the hydrogen from one of the carbon of the ethine, and form a carbanion. This will react with the propane bromide, displacing the bromine and forming a 5 carbon chain with the triple bond on the carbon 1 and 2.
In the second step, reacts with the lindlar catalyst to do a reduction, and form a double bond between carbon 1 and 2. In essence, compound A is similar to compound B.
Finally B reacts with water in acid and makes a addition reaction, and form an alcohol.
The whole process can be seen in the picture below.
Hope this helps
