Answer:
D
Explanation:
Just look at the groups and their tendencies. Or look at their electron configurations. You will notice that calcium has 2 valence electrons and bromine has 7 valence electrons.
Halogens have the most valence electrons possible without completing a shell (8 would be needed for that)
Answer:
In order to be able to solve this problem, you will need to know the value of water's specific heat, which is listed as
c=4.18Jg∘C
Now, let's assume that you don't know the equation that allows you to plug in your values and find how much heat would be needed to heat that much water by that many degrees Celsius.
Take a look at the specific heat of water. As you know, a substance's specific heat tells you how much heat is needed in order to increase the temperature of 1 g of that substance by 1∘C.
In water's case, you need to provide 4.18 J of heat per gram of water to increase its temperature by 1∘C.
What if you wanted to increase the temperature of 1 g of water by 2∘C ?
This will account for increasing the temperature of the first gram of the sample by n∘C, of the the second gramby n∘C, of the third gram by n∘C, and so on until you reach m grams of water.
And there you have it. The equation that describes all this will thus be
q=m⋅c⋅ΔT , where
q - heat absorbed
m - the mass of the sample
c - the specific heat of the substance
ΔT - the change in temperature, defined as final temperature minus initial temperature
In your case, you will have
q=100.0g⋅4.18Jg∘C⋅(50.0−25.0)∘C
q=10,450 J
Answer:
The number of mol is: 0, 042 mol in 4 grams of MgCl2
Explanation:
We calculate the weight of 1 mol of MgCl2:
Weight 1mol of MgCl2= weight Mg + (weight Cl)x 2=
24, 3 grams + 2 x 35, 5 grams = 95, 3 grams/mol MgCl2
95, 3 grams------1 mol MgCl2
4 grams -------x = (4 grams x1 mol MgCl2)/ 95, 3 grams= 0, 04197 mol MgCl2
Answer:
4Fe + 3O₂ → 2Fe₂O₃
Explanation:
Fe → ²⁺
O → ²⁻
But Iron III is Fe³⁺
So we have Fe³⁺ and O²⁻, the formula for the oxide must be Fe₂O₃ so the equation can be:
4Fe + 3O₂ → 2Fe₂O₃
Answer:
The percentage deviation is 
%
Explanation:
From the question we are told that
The concentration is of the solution is 
The true absorbance A = 0.7526
The percentage of transmittance due to stray light 
% 
Generally Absorbance is mathematically represented as
Where T is the percentage of true transmittance
Substituting value
%
The Apparent absorbance is mathematically represented
Substituting values
= 0.7385
The percentage by which apparent absorbance deviates from known absorbance is mathematically evaluated as
%
Since Absorbance varies directly with concentration the percentage deviation of the apparent concentration from know concentration is
%
