Answer:
An atom is composed of a positively-charged nucleus, with a cloud of negatively-charged electrons surrounding it, bound together by electrostatic force. ... Protons and neutrons are bound together to form a nucleus by the nuclear force.
Answer:
4.74 × 10³ mg
Explanation:
Given data
- Health risk limit for chloroform in groundwater: 60.0 g/L
- Volume of the sample of groundwater: 79.0 mL = 79.0 × 10⁻³ L
The maximum mass of chloroform that there could be in the sample of groundwater to meet the standards are:
79.0 × 10⁻³ L × 60.0 g/L = 4.74 g
1 gram is equal to 10³ milligrams. Then,
4.74 g × (10³ mg/1 g) = 4.74 × 10³ mg
Answer:
0.00125 moles H₃X
Solution and Explanation:
In this question we are required to calculate the number of moles of triprotic acid neutralized in the titration.
Volume of NaOH used = final burette reading - initial burette reading
= 39.18 ml - 3.19 ml
= 35.99 ml or 0.03599 L
Step 1: Moles of NaOH used
Number of moles = Molarity × Volume
Molarity of NaOH = 0.1041 M
Moles of NaOH = 0.1041 M × 0.03599 L
= 0.00375 mole
Step 2: Balanced equation for the reaction between triprotic acid and NaOH
The balanced equation is;
H₃X(aq) + 3NaOH(aq) → Na₃X(aq) + 3H₂O(l)
Step 3: Moles of the triprotic acid (H₃X used
From the balanced equation;
1 mole of the triprotic acid reacts with 3 moles of NaOH
Therefore; the mole ratio of H₃X to NaOH is 1 : 3.
Therefore;
Moles of Triprotic acid = 0.00375 mole ÷ 3
= 0.00125 moles
Hence, moles of triprotic acid neutralized during the titration is 0.00125 moles.
Answer:
The correct answer would be - 13.0975 ounces.
Explanation:
We know that brass is made up of zinc and copper. The copper part of the brass is approximately around 50 to 70% and the remaining is the zinc part.
Given:
Zinc percentage in a brass = 35%
copper percentage would be - 65% (100 - 35 = 65)
Weight of the brass metal bar = 20.15 ounce
ounces of copper are in the bar = ?
Solution:
The weight of the copper in the brass metal in ounces-
= weight of brass* percentage of copper/100
= 20.15*65/100
= 13.0975 ounces of copper.
2nd method =
The weight of the zinc in the brass metal in ounces-
= weight of brass* percentage of zinc/100
= 20.15*35/100
= 7.0525
The weight of the copper = total weight - weight of zinc
= 13.0975 ounces of copper.
