Answer:
Explanation:
Given:
For a school event, 1/6 of the athletic field is reserved for the fifth -grade classes and the reserved part of the field is divided equally among the 4 fifth grade classes in the school.
To find: fraction of the whole athletic field reserved for each fifth class
Solution:
Fraction of the whole athletic field reserved for four fifth classes = 
So, fraction of the whole athletic field reserved for each fifth class = 
The first thing we need to do here is to recognize the unit of molarity and the units of the given percentage of nitric acid.
Molarity is mol HNO3 / L of solution. This is our aim
The given percentage is 0.68 g HNO3/ g solution
multiplying this with density to convert g solution into mL solution and dividing with the molecular weight of HNO3 (63 g/mol) to convert g HNO3 to mol. Therefore we obtain
0.016 mol/ mL or 16.23 mol/ L (M)
If you look on the periodic table (especially one online) you can see that it is colour coded...so this might help...
If you look you can see a "staircase"..which consists of B, Si, Ge, As, Sb, Te, Po...If it is on the lefthand side of the staircase it is a metal (ie: Ni) or if it is on the righthand side it is a non metal. There is lots of images on google that can help point it out.
If you are talking in terms of properties you should look for (Metal) materials that are:
<span>Lustrous
Hard.
High density (heavy for their size)
High strength (resist being stretched)
High melting and boiling points.
<span>Good conductors of heat and electricity.
Non metals are/have:
</span></span><span>High ionization
High electronegativities
Not malleable or ductile.
Little or no metallic luster.
Gain electrons easily.
<span>Dull, not metallic-shiny
</span></span>poor conductors of heat
and poor conductors of electricity
Hope this helps!
Answer:
A SOLUTION THAT REGULATES pH BECAUSE IT IS SUCH A STRONG ACID OR BASE
Explanation:
A buffer solution is an aqueous solution consisting of a weak acid and its conjugate base. It is an aqueous solution used to keep the pH of solution at a nearly constant value in various chemical processes. It resists change in pH when either a strong acid or a strong base is added. So it is very essential in various chemical applications and even in the human body as the blood pH is kept in nearly constant value by the bicarbonate buffer system in conjunction with the kidneys. The buffer solution is able to keep this nearly constant range of values because of the equilibrium between the weak acid and its conjugate base. So therefore, the incorrect statement in the options is that buffer solution is a solution that regulates pH because it is such a strong acid or base. The other options are correct.
Answer:
The correct answer is 0.165 g NaCl.
Explanation:
The following is the precipitation reaction taking place between sodium chloride and silver nitrate:
NaCl (aq) + AgNO₂ (aq) ⇒ NaNO₃ (aq) + AgCl (s)
The complete ionic reaction of the reaction will be,
Na⁺ + Cl⁻ + Ag⁺ + NO₃⁻ ⇒ AgCl (s) + Na⁺ + NO₃⁻
Hence, the net ionic equation for the mentioned reaction is:
Ag⁺ (aq) + Cl⁻ (aq) ⇒ AgCl (s)
Thus, it can be witnessed that one mole of chloride ion is needed so that one mole of Ag⁺ ion get neutralized. There is a need to find the moles of silver ions present in the solution of AgNO₃ and then transform these moles to the moles of chloride ion. Ultimately, these moles can be converted to the concentration of sodium chloride needed.
The no. of moles of silver ions found in silver nitrate solution is,
(2.50 × 10² mL) × (0.0113 mol Ag⁺/1000 ml solution) = 2.83 × 10⁻³mol Ag⁺
Now the moles of chloride ions needed to precipitate the silver ions is,
(2.83 × 10⁻³ mol Ag⁺ ) × (1 mol Cl⁻/1 mol Ag⁺) = 2.825 × 10⁻³mol Cl⁻
The mass of sodium chloride needed for precipitating the silver ions will be,
mass of NaCl = (2.83 × 10⁻³ mol Cl⁻) × (1 mol NaCl / 1 mol Cl⁻) × (58.44 grams / 1 mol NaCl)
= 0.165 gram NaCl.
