Answer:
The percent error of student is -5 %.
Explanation:
Given data:
measured value = 9.31 m/s²
actual value = 9.8 m/s²
percent error = ?
Formula:
% error = (measured value - actual value / actual value ) × 100
% error = (9.31 m/s² - 9.8 m/s² / 9.8 m/s²) × 100
% error = (-0.49 m/s² / 9.8 m/s²) × 100
% error = -0.05 × 100
% error = -5
<span>The preparation of 40 liters of 0.02 m phosphate buffer, ph 6.9, may be carried out by adding 132g of solid trisodium phosphate to 1290ml of hydrochloric acid (HCl concentration 1 mol/L), then making up to a final liquid volume of 40 liters by adding water.
Method: Weigh out 132 grams of Na3PO4 (s), and add it to 1290 ml 1M HCl (l). Mix, then add water, to a final volume of 40 liters.</span>
The correct option is
<span>D. Observation....</span>
Answer : The formal charge on central Cl atom is -1.
Explanation :
The given molecule is,
First we have to determine the total number of valence electrons in,
As we know, chlorine has 7 valence electrons.
Total number of valence electrons in = 3(7) + 1 = 22 electrons
Electrons used in bonding pair = 4
Electrons used as lone pair = 22 - 4 = 18
Now we have to calculate the formal charge on central Cl atom.
- Formal charge = Number of valence electrons of a central atom - (2 × Number of lone pairs) - Number of bond pairs
Formal charge on central Cl atom = 7 - (2 × 3) -2 = -1
Therefore, the formal charge on central Cl atom is -1.
The lewis-dot structure of is shown below.
The weight of the container after the wax hardens is 0.18 N.
<h3>What is the law of conservation of mass?</h3>
We know that according to the law of the conservation of mass, the mass of an object can neither be created nor destroyed but it can be changed from one form to the other.
Looking at this law, we know that the mass would not change even after the time that the wax must have hardened. The total mass of the wax would have to be a constant.
Total mass would now be;
Mass of the wax + mass of the container
= 3 g + 15 g
= 18 g
Weight = 18/1000 * 9.8 m/s^2
= 0.18 N
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