Disaccharide forms when two monomers join.
Answer:
(Most accurate) pippete>graduated cylinder>beaker>balance (Least accurate)
Explanation:
- <em>Most accurate. A pipette prived the most accurate method for delivering a known volume of solution, for example, a 10mL transfer pipette has an accuracy of ±0.02mL</em>
- A graduated cylinder is specifically used to deliver a known volume, its typical accuracy is ±1%, this means that a 100ml graduated cylinder is accurate to ±1mL.
- A beaker is a multipurpose cylindrical glass mainly used to hold liquids. Even though they are graduated, these marks are an estimation, the beaker's accuracy is around 10%.
- Least accurate. A balance measures an object's mass, even though water's density is close to 1, a balance is not the ideal equipment to measure volume, its capacity usually goes between 100-200grams and can measure mass to the nearest ±0.01mg to ±1mg.
I hope you find this information useful and interesting! Good luck!
Answer:
46.40 g.
Explanation:
- It is a stichiometric problem.
- The balanced equation of the reaction: 4K + O₂ → 2K₂O.
- It is clear that 4.0 moles of K reacts with 1.0 mole of oxygen produces 2.0 moles of K₂O.
- We should convert the mass of K (38.5 g) into moles using the relation:
<em>n = mass / molar mass,</em>
n = (38.5 g) / (39.098 g/mol) = 0.985 mole.
<em>Using cross multiplication:</em>
4.0 moles of K produces → 2.0 moles of K₂O, from the stichiometry.
0.985 mole of K produces → ??? moles of K₂O.
∴ The number of moles of K₂O produced = (0.985 mole) (2.0 mole) / (4.0 mole) = 0.4925 mole ≅ 0.5 mole.
- Now, we can get the mass of K₂O:
∴ mass = n x molar mass = (0.5 mole) (94.2 g/mol) = 46.40 g.
According to the reaction equation:
and by using ICE table:
CN- + H2O ↔ HCN + OH-
initial 0.08 0 0
change -X +X +X
Equ (0.08-X) X X
so from the equilibrium equation, we can get Ka expression
when Ka = [HCN] [OH-]/[CN-]
when Ka = Kw/Kb
= (1 x 10^-14) / (4.9 x 10^-10)
= 2 x 10^-5
So, by substitution:
2 x 10^-5 = X^2 / (0.08 - X)
X= 0.0013
∴ [OH] = X = 0.0013
∴ POH = -㏒[OH]
= -㏒0.0013
= 2.886
∴ PH = 14 - POH
= 14 - 2.886 = 11.11
1.53 moles of Fe is your solution hope it helps!
