Answer:
2
Explanation:
1. The dew is formed when the water vapor at the atmosphere contacts the leaves, which are at a low temperature, so, the vapor temperature decreases, and the liquid is formed. So, it's a gas to liquid change.
2. Ice cubes are at the solid-state, thus this transformation is solid to a liquid change.
3. The cold juice is at a low temperature, so when the water vapor of the air contacts with the glass, its temperature decreases, and its change to a liquid phase. So, it's a gas to liquid change.
4. The evaporated water from the Earth's surface goes to the atmosphere, and, at high altitudes, the temperature is low, so the water vapor condenses and the drops get closer together forming the clouds. So, it's a gas to a liquid change.
To determine the velocity of an object, you need to know the displacement and the change in time.
v = displacement / change in time
write the equation for the reaction
that is 6 F2 +P4 =4 PF3
find the theoretical mass that is
let the theoretical yield be represented by y
theoretical yield = 78.1/100 = 120/y
y= 153.6 grams
find the number of moles of PF3
moles = mass/molar mass
= 153.6/87.97 =1.746 moles
by use of mole ratio between F2 :PF3 which is 6:4 the moles of F2 is therefore= 1.746 x 6/4 = 2.62 moles
mass = moles x molar mass
= 1.746 moles x38 g/mol = 99.6 grams
Stoichiomety:
1 moles of C + 1 mol of O2 = 1 mol of CO2
multiply each # of moles times the atomic molar mass of the compund to find the relation is weights
Atomic or molar weights:
C: 12 g/mol
O2: 2 * 16 g/mol = 32 g/mol
CO2 = 12 g/mol + 2* 16 g/mol = 44 g/mol
Stoichiometry:
12 g of C react with 32 g of O2 to produce 44 g of CO2
Then 18 g of C will react with: 18 * 32/ 12 g of Oxygen = 48 g of Oxygen
And the result will be 12 g of C + 48 g of O2 = 60 g of CO2.
You cannot obtain 72 g of CO2 from 18 g of C.
May be they just pretended that you use the law of consrvation of mass and say that you need 72 g - 18g = 54 g. But it violates the proportion of C and O2 in the CO2 and is not possible.
Answer:
the answer is D
Explanation:
percentage composition= mole of the substance divided by the total molar mass of the compound multiplied by 100.
