In order to answer this, we mus know the data for the heat of combustion of propane. This is an empirical data that you can search online. The heat of combustion is -2220 kJ/mol. The molar mass of propane of 44.1 g/mol. The solution is as follows:
ΔH = -2220 kJ/mol (1 mol/44.1 g)(1000g/1kg)(20 kg)
<em>ΔH = -1006802.721 kJ or -1 GJ</em>
Answer:
Mass = 76.176 g
Explanation:
Given data:
Mass of lead(II) chloride produced = 62.9 g
Mass of lead(II) nitrate used = ?
Solution:
Chemical equation:
Pb(NO₃)₂ + 2HCl → PbCl₂ + 2HNO₃
Number of moles of lead(II) chloride:
Number of moles = mass/molar mass
Number of moles = 62.9 g/ 278.1 g/mol
Number of moles = 0.23 mol
Now we will compare the moles of lead(II) chloride with Pb(NO₃)₂ from balance chemical equation:
PbCl₂ : Pb(NO₃)₂
1 : 1
0.23 : 0.23
Mass of Pb(NO₃)₂:
Mass = number of moles × molar mass
Mass = 0.23 mol × 331.2 g/mol
Mass = 76.176 g
Most of the elements important in biology need eight electrons in their outermost shell in order to be stable, and this rule of thumb is known as the octet rule. Some atoms can be stable with an octet even though their valence shell is the 3n shell, which can hold up to 18 electrons.
The Mohs scale is for natural minerals<span>. For manufactured products other measures of hardness are better. ... There are ten </span>minerals<span> in Mohs scale, talc, gypsum, calcite, fluorite, apatite, orthoclase, quartz, topaz, corundum, and for last and</span>hardest<span>, diamond.
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The heat needed to raise the temperature of 50g of substance by 15 c is calculated as follows
Heat = mc delta T
m= mass (50g)
c= specific heat capacity (0.92)
delta T= change in temperature( 15 c)
heat is therefore= 50 x 0.92 x 15 = 690
Nb: my answer has no units since the given specific heat capacity has no units
