Answer:
665 kJ
Explanation:
We assume that carbohydrates and protein each have 4 kilocalories per gram, and that fat has 9 kilocalories per gram. Then the number of kilocalories in the peanut butter is ...
4(6 +9) +9(11) = 159 . . . . kilocalories
Each kilocalorie translates to 4.184 kilojoules, so the total is ...
(159 kCal)(4.184 kJ/kCal) = 665.256 kJ
2 Tbsp of crunchy peanut butter contains about 665 kJ of energy.
Answer:
d. 12.3 grams of Al2O3
Explanation:
The balanced chemical equation of this chemical reaction is as follows:
4Al + 3O2 --> 2Al2O3
Based on the balanced equation, 4 moles of aluminum (limiting reagent) reacts to form 2 moles of aluminum oxide (Al2O3).
First, we need to convert the mass of aluminum to moles using the formula;
mole = mass/molar mass
Molar mass of Al = 27g/mol
mole = 6.50/27
= 0.241mol of Al.
Hence, if 4 moles of aluminum (limiting reagent) reacts to form 2 moles of aluminum oxide (Al2O3).
Then, 0.241mol of Al will produce (0.241 × 2/4) = 0.241/2 = 0.121mol of Al2O3.
Convert this mole value to molar mass using mole = mass/molar mass
Molar mass of Al2O3 = 27(2) + 16(3)
= 54 + 48
= 102g/mol
mass = molar mass × mole
mass = 102 × 0.121
mass of Al2O3 = 12.34grams.
The answer is d
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Answer:
Explanation:
Compounds consist of atoms of different elements. In compound the atoms are present in fixed proportion. By changing the proportion compound will changed. For example,
Nitrogen and oxygen reacted to form the compound. By changing the proportion both will form different compound.
NO₂
Nitrogen dioxide consist of one atom of nitrogen and two atoms of oxygen. Their ration is 1 :2
NO
In nitric oxide one atom of oxygen and one atom of nitrogen are present.
Their ratio is 1 : 1.
N₂O
Nitrous oxide consist of two nitrogen atoms and one oxygen. Their ratio is
2 : 1
N₂O₄
Dinitrogen tetroxide consist of two nitrogen atoms and four oxygen atoms. Their ratio will written as 2 : 4
N₂O₅
Dinitrogen pentoxide consist of two nitrogen atoms and five oxygen atoms. Their ratio will written as 2 : 5
It can be seen that by changing the ratio of atoms compounds are changed.
