Answer:
5
Explanation:
They have 5 in common but different x
Answer: 72 grams of
are needed to completely burn 19.7 g 
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass and contains avogadro's number
of particles.
To calculate the number of moles, we use the equation:

Putting in the values we get:


According to stoichiometry:
1 mole of
requires 5 moles of oxygen
0.45 moles of
require=
moles of oxygen
Mass of 
72 grams of
are needed to completely burn 19.7 g 
Answer:
C) 2 Na + 2 H2O → 2 NaOH + H2.
Explanation:
Hello there!
In this case, according to the given chemical reactions, it is possible to firstly understand that a single displacement reaction is characterized by the presence of a single element as the first reactant and a compound as the second one, thus, yielding a compound as the first product and a single element as the second one.
In such a way, according to the given choices, it possible to note that C) 2 Na + 2 H2O → 2 NaOH + H2 is the only one with the aforementioned condition as the element at the reactants side is Na and at the products side is H2.
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Answer:
Mass = 0.32 g
Explanation:
Given data:
Mass of CH₄ = ?
Volume of CH₄ = 500 mL (500 mL× 1L/1000 mL= 0.5 L)
Temperature = 273 K
Pressure = 1 atm
Solution:
Volume of CH₄:
500 mL (500 mL× 1L/1000 mL= 0.5 L)
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
By putting values,
1 atm× 0.5 L = n×0.0821 atm.L/ mol.K × 273 K
0.5 atm.L = n×22.4 atm.L/ mol
n = 0.5 atm.L / 22.4 atm.L/ mol
n = 0.02 mol
Mass in gram:
Mass = number of moles × molar mass
Mass = 0.02 mol × 16 g/mol
Mass = 0.32 g