Answer:
A. True
Explanation:
The octane number is determined by comparing the characteristics of gasoline to isooctane (2,2,4-trimethylpentane) and heptane. The correct option is option A.
Basically, the higher the octane number, the greater the resistance of the gasoline to knocking.
The correct answer is 96.80 grams
Explanation:
The density of a substance shows the total mass the substance contains in 1 mL or 1 cm3 as density is calculated by using the formula D= M (mass) / V (volume). This implies, Iron contains 7.87 grams per milliliter. Moreover, this value and formula can be used to calculate the mass or volume of any other sample. The process to calculate the mass of an iron sample with a volume of 12.3 mL is shown below.
D = M ÷ V
7.87 mL = x ÷ 12.3 mL - x represents the missing value. Now find the value of x by solving the equation
x = 7.87 · 12.3
x = 96.80
This means a sample of 12.3 mL contains a mass of 96.80 grams. Also, you can know this value is correct because if you divide the mass by the value the density is the same (96.80 grams ÷ 12.3 mL = 7.87 g/mL)
Answer:
Locate the element’s atomic number. The atomic number is located above the element symbol, in the upper left-hand corner of the square. The atomic number will tell you how many protons make up a single atom of an element.
Explanation:
1. You can use Avogadro’s number, 6.022x10^23 atoms/mole, to answer this one.
(3.311x10^24/6.022x10^23) = 5.498 moles of substance
2. H2O has a formula weight approximately equal to 18 grams. Dividing the given amount by the formula weight of water will tell us the number of moles present.
126/18 = 7 moles H2O
