Answer:
21.3 g. Option B
Explanation:
The reaction is:
4HF(g) + SiO₂(s) → SiF₄(g) + 2H₂O(g)
We analysed it and it is correctly balanced.
4 moles of hydrogen fluoride react to 1 mol of silicon dioxide in order to produce 1 mol of silicon fluoride and 2 moles of water vapor.
We determine molar mass of each reactant:
HF → 1.01 g/mol + 19 g/mol = 20.01 g/mol
SiO₂ → 16 g/mol . 2 + 28.09 g/mol = 60.09 g/mol
We convert mass to moles: 16 g . 1 mol /60.09g = 0.266 moles of glass
Ratio is 1:4. 1 mol of glass react to 4 moles of HF
Our 0.266 moles may react to (0.266 . 4) / 1 = 1.07 moles of gas
We convert moles to mass: 1.07 mol . 20.01 g/mol = 21.3 g
Cross contamination can be caused by CARRYING DRINKING GLASSES BY THE RIMS.
Cross contamination refers to the transfer of harmful microbes to foods from various sources. The rim of a drinking glass is where you put your mouth when you are drinking from a glass cup. If one is carrying a drinking glass by the rim, one can easily transfer the dirty in one's hand to the glass and this will be ingested by person who use the cup. Drinking glasses should be carried by holding their bases.
Answer:
Area of rectangle = 108 cm²
Given:
Base = 6 cm
Height = 18 cm
Explanation:
Area of rectangle = Base × Height
= 6 × 18
= 108 cm²
Nitrogen and oxygen do not react at ambient temperature. At high temperatures they have endothermic reactions and produces various oxides of nitrogen.
Explanation:
The difference between nitrogen and oxygen is the nitrogen has seven protons and seven electrons surrounding the nucleus. Whereas the oxygen has eight protons and electrons.
The atoms combines with one another to form molecules. The nitrogen is a inert, colorless gas with no smell or taste, its harmless to human beings.
The oxygen and nitrogen are abundant gases in the atmosphere and have similar physical properties. The oxygen (O2) is twice as soluble in water as nitrogen (N2).
The leaf would be on top of the wave after two seconds just like it was positioned at 0 seconds. After 3 seconds the leaf should be positioned like it was at 1 second. The leaf is moving along with the wave.
