First, you need to convert kg to g.
So, 1 kg =1000g.
3.5 x 1000 = 3500g Ca(OH)2
We need to know the molar mass of Ca(OH)2.
Ca= 40.08 g
O=2(15.999)
H=2(1.0079)
Add them all together and you get 74.0938 g.
Put it in the formula from mass to moles.
# of moles = grams Ca(OH)2 x 1 mol Ca(OH)2
--------------------
molar mass Ca(OH)2
3500 g Ca(OH)2 x 1 mol Ca(OH)2
---------------------
74.0938 g Ca(OH)2
So divide 1/74.0938 and multiply by 3500.
You will get about 47.24 moles Ca(OH)2.
Hope this helps! :)
Answer:
Explanation:
In theory, not much of anything. The vast majority of nitrates are water soluble. Aside, not sure what chemistry level you are at but you will probably be asked to know or memorize some solubility rules. This, for lack of a better phrase, Nitrate rule, is near spot on. With one exception—a rare one—all metal cationic nitrates are soluble in water. All of them. So, assuming you are talking about aqueous, water-based solutions of these salts and mixing them together, I expect nothing to occur. Both solutions, I believe are colorless in water and will thus remain so. If you had say a solution of Iron (III) nitrate and copper (II) nitrate, slightly different story. Both are colorful solutions and I would think you might see blending of colors but no reaction; no precipitate will form. You will probably learn about markers of a chemical reaction. One of these is a color change. Note, you should read this as a change of color from what you previously had. Going from red to blue or colorless to colored (or vice versa) is a strong indication of a reaction (e. g. evidence of bond-breaking and bond-formation). The mere mixing of colors does not constitute a chemical reaction.
Mixtures are made up of 2 or more pure substances. pure substance is just its self and a mixture is multiple substances.
Answer:
% = 76.75%
Explanation:
To solve this problem, we just need to use the expressions of half life and it's relation with the concentration or mass of a compound. That expression is the following:
A = A₀ e^(-kt) (1)
Where:
A and A₀: concentrations or mass of the compounds, (final and initial)
k: constant decay of the compound
t: given time
Now to get the value of k, we should use the following expression:
k = ln2 / t₁/₂ (2)
You should note that this expression is valid when the reaction is of order 1 or first order. In this kind of exercises, we can assume it's a first order because we are not using the isotope for a reaction.
Now, let's calculate k:
k = ln2 / 956.3
k = 7.25x10⁻⁴ d⁻¹
With this value, we just replace it in (1) to get the final mass of the isotope. The given time is 1 year or 365 days so:
A = 250 e^(-7.25x10⁻⁴ * 365)
A = 250 e^(-0.7675)
A = 191.87 g
However, the question is the percentage left after 1 year so:
% = (191.87 / 250) * 100
<h2>
% = 76.75%</h2><h2>
And this is the % of isotope after 1 year</h2>
Answer:
The correct option is:
A) by direct or indirect contact between objects at different temperatures
Explanation:
Heat can be transferred in three different methods:
Conduction, Convection and Radiation
Conduction is heat transfer through direct contact between substances at different temperatures.
Convection is the heat transfer which takes place through air currents.
Radiation is the heat transfer that does not require contact between two objects.
Hence, heat transfer can take place through direct or indirect contact between objects at different temperatures.
