To determine the mass of the hydrogen gas that was collected, we calculate for the moles of hydrogen gas from the conditions given. In order to do this, we need an equation which would relate pressure, volume and temperature. For simplicity, we assume the gas is an ideal gas so we use the equation PV = nRT where P is the pressure, V is the volume, n is the number of moles of the gas, T is the temperature and R is the universal gas constant. We calculate as follows:
PV = nRT
n = PV / RT
n = (18.6/760) (7.80) / 0.08205 ( 21 + 273.15)
n = 0.0079 mol
Mass = 0.0079 mol ( 18.02 g / mol ) = 0.1425 g H2
Answer: Heating a crucible to remove water from a hydrate.
Explanation:
The options are:
a. Heating a solvent to help a solute dissolve.
b. Heating an isolated solid to dry it.
c. Heating water to boiling for a water bath.
d. Heating a crucible to remove water from a hydrate.
The procedure that can be performed on a hot plate are:
a. Heating a solvent to help a solute dissolve.
b. Heating an isolated solid to dry it.
c. Heating water to boiling for a water bath.
It should be noted that the hot plate cannot be used for heating of crucible in order to remove water from a hydrate. It is not advisable for someone to heat any silica or ceramic objects on a hot plate.
Therefore, heating a crucible to remove water from a hydrate is the correct option.
Answer:
The volume that this same amount of air will occupy in his lungs when he reaches a depth of 124 m is - 0.27 L.
Explanation:
Using Boyle's law

Given ,
V₁ = 3.6 L
V₂ = ?
P₁ = 1.0 atm
P₂ = 13.3 atm (From correct source)
Using above equation as:




The volume that this same amount of air will occupy in his lungs when he reaches a depth of 124 m is - 0.27 L.
Answer is: the mass of a block of magnesium is 177.75 grams.
m(Fe) = 826 g.
d(Fe) = 7.9 g/cm³.
1) Calculate volume of iron and magnesium:
d(Fe) = m(Fe) ÷ V(Fe).
V(Fe) = m(Fe) ÷ d(Fe).
V(Fe) = 826 g ÷ 7.9 g/cm³.
V(Fe) = V(Mg) = 104.56 cm³.
2) Calculate mass of magnesium:
m(Mg) = V(Mg) · d(Mg).
m(Mg) = 104.56 g/cm³ · 1.7 g/cm³.
m(Mg) = 177.75 g.
Answer:
False. It should read that both plant and animal species are in danger of extinction, and climate change can destroy habitats.
Explanation: