The number 23.0702 has 6 significant figures.
To answer this, you must have the rules for significant figures,
1. All non-zero numbers ARE significant
2. Zeros between two non-zero digits ARE significant
3. Leading zeros are NOT significant
4. Trailing zeros are ONLY significant if the number has a decimal point
The number 23.0702 has 4 non-zero numbers(rule 1), and both zeros are between two non-zero digits(rule 2). Since all 6 figures in the number 23.0702 are significant, the number 23.0702 has 6 significant figures.
That would be an ionic bond since it has electrons to spare, rather than a convalent bond where all the electrons are taken up thus it is not a good conductor
The solution is here,
given mass of copper wire(m)=25 g
no. of moles in given mass of Cu=0.393
a) no. of atoms= no. of moles×avogardo's number
=0.393×6.023×10^23=2.36 ×10^23 atoms
b) 25 g of Cu wire has 0.393 moles
so 200 g of Cu wire has 0.393/25 × 200=3.144 mol.
no. of atoms= 3.144×2.023×10^23=1.89×10^24 atoms.
c) 25 g of Cu wire has 2.36×10^23 atoms
so 5 g of Cu wire has (2.36×10^23)/25 × 5
=4.72×10^22 atoms
( b can also be solve like c)
Total mass of mouthwash = volume*density
1 pint is 568.261 mL therefore 1.040 pints = 591.0 mL (4 significant figures)
Therefore mouthwash mass in a bottle = 591.0 mL * 0.851 g/mL = 503 g (3 s.f.)
In 160 bottles, ethanol mass = 509 g * 160 * 0.381 = 30700 g = 30.7 kg
Answer:
Option D. 17.5
Explanation:
Equiibrium is: CO + 2H₂ ⇄ CH₃OH
1 mol of CO is in equibrium with 2 moles of hydrogen in order to make, methanol.
Initially we have 0.42 moles of CO and 0.42 moles of H₂
If 0.29 moles of CO remained, (0.42 - 0.29) = 0.13 moles have reacted.
So in the equilibrium we may have:
0.29 moles of CO, and (0.42 - 0.13 . 2) = 0.16 moles of H₂
Ratio is 1:2, if 0.13 moles of CO haved reacted, (0.13 . 2) moles have reacted of hydrogen
Finally 0.13 moles of methanol, are found after the equilibrium reach the end.
Let's make expression for KC: [Methanol] / [CO] . [Hydrogen]²
0.13 / (0.29 . 0.16²)
Kc = 17.5
