What is the density of an object that has a mass of 149. 8 g and displaces 12. 1 ml of water when placed in a graduated cylinder
1 answer:
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Answer : The chemical formula of a compound is,
Solution : Given,
Mass of gallium = 1.25 g
Mass of gallium oxide = 1.68 g
Mass of oxygen = Mass of gallium oxide - Mass of gallium
Mass of oxygen = 1.68 - 1.25 = 0.43 g
Molar mass of Ga = 69.72 g/mole
Molar mass of O = 16 g/mole
Step 1 : convert given masses into moles.
Moles of Ga =
Moles of O =
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For Ga =
For O =
The ratio of Ga : O = 1 : 1.5
To make in whole number we multiple ratio by 2, we get:
The ratio of Ga : O = 2 : 3
The mole ratio of the element is represented by subscripts in empirical formula.
The Empirical formula =
The empirical formula weight = 2(69.72) + 3(16) = 187.44 gram/eq
Now we have to calculate the molecular formula of the compound.
Formula used :
Molecular formula =
Therefore, the chemical of the compound is,
corrected question:
Determining Density and Using Density to Determine Volume or Mass
(a) Calculate the density of mercury if 1.00 × 10 g occupies a volume of 7.36 cm³
(b) Calculate the volume of 65.0 g of liquid methanol (wood alcohol) if its density is 0.791 g/mL.
(c) What is the mass in grams of a cube of gold (density = 19.32 g/cm) if the length of the cube is 2.00 cm?
(d) Calculate the density of a 374.5-g sample of copper if it has a volume of 41.8 cm³ A student needs 15.0 g of ethanol for an experiment. If the density of ethanol is 0.789 g/mL, how many milliliters of ethanol are needed? What is the mass, in grams, of 25.0 mL of mercury (density = 13.6 g/mL)?
Answer:
density =
ρ=m/v ,m=ρv, v=m/ρ
(a)m=1*10g , v=7.36cm³
ρ=10/7.36 =1.36g/cm³
(b) m=65g, ρ=0.791 g/mL.
v= 65/0.791 =82.17g/mL
(c) ρ=19.32g/cm³, l=2cm, v=l³=8cm³
m=19..32*8=154.56g/cm³
(d) mass of copper=374.5g , v=41.8cm³
ρ=374.5/41.8 =8.96g/cm³
mass of ethanol=15g, density of ethanol=0.789g/mL
v=15/0.789 =19.01mL
volume of mecury=25mL, density of mercury=13.6g/mL
m=25*13.6=340g