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<span>A chemical that will ignite spontaneously in air at a temperature of 130 degree fahrenheit (54.4 degree celsius) or below is identified by the term pyrophoric.
Pyrophoric substances are those that ignite spontaneously when in contact with air at 130 °F or below. Some substances that are pyrophoric include Iron Sulfur (FeS) or some metals like finely powdered Uranium. To handle pyrophoric substances, it is required to work in an inert atmosphere (i.e. an atmosphere without oxygen).
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Answer:
The mass is 0.855 grams (option A)
Explanation:
Step 1: Data given
aluminium sulfate = Al2(SO4)3
Numer of moles Al2(SO4)3 = 2.50 * 10^-3 moles
atomic mass Al = 26.99 g/mol
atomic mass S = 32.065 g/mol
Atomic mass O = 16 g/mol
Step 2: Calculate molar mass Al2(SO4)3
Molar mass = 2* 26.99 + 3*32.065 + 12*16
Molar mas = 342.175 g/mol
Step 3: Calculate mass Al2(SO4)3
Mass Al2(SO4)3 = moles Al2(SO4)3 * molar mass Al2(SO4)3
Mass Al2(SO4)3 = 2.5 *10^-3 moles * 342.175 g/mol
Mass Al2(SO4)3 = 0.855 grams
The mass is 0.855 grams (option A)
Answer:
6.25 ×10^10 Hz
Explanation:
If the distance between five successive crests is 2.4 cm, then the distance between each crest is 2.4/5 = 0.48 cm or 0.0048 m or 4.8 ×10^-3 m
Since the velocity of a wave is given by;
v= λf
Where;
λ= wavelength of the wave
f= frequency of the wave
But λ= distance between successive crests = 4.8 ×10^-3 m
v= 3×10^8 ms-1 (speed of electromagnetic waves in vacuum)
f= v/λ
f= 3×10^8 ms-1/4.8 ×10^-3 m
f= 0.625 ×10^11 Hz
f= 6.25 ×10^10 Hz
Answer:
A. The sum of the voltages of the half-reactions is positive.
Explanation:
correct on a p e x
The average atomic mass is calculated by the expression:
Average atomic mass = Σzₓ(Aₓ)
where zₓ is the relative abundance of an isotope and Aₓ is the atomic mass of the isotope.
We calculate the mass of the isotope as follows:
10.81 = .1980 (10.012938) + .8020 (x)
x = 11.00 -----------> mass of the isotope
