<span>1.) a. 20 ÷ 4 ? means ? × 4 = 20 </span>→ replace ? with 5.<span>
b. 2,725 ÷ 5 ? means ? × 5 = 2,725 </span>→ replace ? with 545<span>
c. ? ÷ 5 = 0 </span>→ replace ? with 0.
2) 1,475 / 25 = 59
They used 59 boxes for this year.
3) 18 per haircut ; 70 per perm
4,608 = 18h + 70(36)
4,608 - 2,520 = 18h
2,088 = 18h
2,088/18 = h
116 = h
Grace did 116 haircuts.
4) 575 + 13(118) = 575 + 1,534 = 2,109 total expense.
5) 2,240 miles / 320 miles = 7 tanks of gas used.
7 tanks * 39 = 273 cost of the gas used.
The units of light energy emitted by blackbody radiation is originally called as quanta. Black body radiation is a type of radiation within a boy in thermodynamic equilibrium. This is a theoretical body. In 1900, Planck proposed that light and other electromagnetic waves were emitted in discrete packets of energy which were called "quanta". This was the original unit used.
Answer:
0.50 mol
Explanation:
The half-life is <em>the time required for the amount of a radioactive isotope to decay to half that amount</em>.
Initially, there are 8.0 moles.
- After 1 half-life, there remain 1/2 × 8.0 mol = 4.0 mol.
- After 2 half-lives, there remain 1/2 × 4.0 mol = 2.0 mol.
- After 3 half-lives, there remain 1/2 × 2.0 mol = 1.0 mol.
- After 4 half-lives, there remain 1/2 × 1.0 mol = 0.50 mol.
1. D. 5
2. B. 2
3. A. fluroine
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<span>: The empirical formula for the compound is C3H60 (see below)
CO2 is the only product containing C,
C produced = 145.0 mg CO2 x (1 g / 1000 mg) x (1 mole CO2 / 44.0 g CO2) x (1 mole C / 1 mole CO2) = 0.00330 moles C.
H2O is the only product containing H,
H produced = 59.38 mg H2O x (1 g / 1000 mg) x (1 mole H2O / 18.0 g H2O) x (2 moles H / 1 mole H2O) = 0.00660 moles H.
Oxygen is in both and the unknown reacts with oxygen(in the air)
0.00330 moles C x (12.0 g C / 1 mole C) = 0.0396 g C = 39.6 mg C
0.00660 moles H x (1.01 g H / 1 mole H) = 0.00667 g H = 6.7 mg H
Because the unknown weighed 63.8 mg and consists off justC, H, and O, then
mass O = g unknown - g C - g H = 63.8 mg - 39.6 mg - 6.7 mg = 17.5 mg = 0.0175 g
0.0175 g O x (1 mole O / 16.0 g O) = 0.00109 moles O
The mole ratio of C:H:O is:
C = 0.00330
H = 0.00660
O = 0.00109
Divide by the smallest you get:
C = 0.00330 / 0.00109 = 3.03
H = 0.00660 / 0.00109 = 6.06
O = 0.00109 / 0.00109 = 1.00</span>
