Answer:
Its already balanced
Explanation:
Ba (barium) starts with and ends with 1. Br (bromine) starts with 2 and ends with 2. 
 
        
                    
             
        
        
        
Explanation:
1) Initial mass of the Cesium-137= = 180 mg
= 180 mg
Mass of Cesium after time t = N
Formula used :
 
Half life of the cesium-137 = ![t_{1/2}=30 years[p/tex]where,
[tex]N_o](https://tex.z-dn.net/?f=t_%7B1%2F2%7D%3D30%20years%5Bp%2Ftex%5D%3C%2Fp%3E%3Cp%3Ewhere%2C%0A%3C%2Fp%3E%3Cp%3E%5Btex%5DN_o) = initial mass of isotope
 = initial mass of isotope
N = mass of the parent isotope left after the time, (t)
 = half life of the isotope
 = half life of the isotope
 = rate constant
 = rate constant

Now put all the given values in this formula, we get
 
 Mass that remains after t years.

Therefore, the parent isotope remain after one half life will be, 100 grams.
2)
t = 70 years


 
N = 35.73 mg
35.73 mg of cesium-137 will remain after 70 years.
3) 


N = 1 mg
t = ?
 

t = 224.80 years ≈ 225 years
After 225 years only 1 mg of cesium-137 will remain.
 
        
             
        
        
        
Answer:
I'm pretty sure that's right.
Explanation:
 
        
             
        
        
        
When the Pka for formic acid = 3.77
and Pka = -㏒ Ka 
   3.77 = -㏒ Ka
∴Ka = 1.7x10^-4 
when Ka = [H+][HCOO-}/[HCOOH]
when we have Ka = 1.7x10^-4 &[HCOOH] = 0.21 m
so by substitution: by using ICE table value
1.7x10^-4 = X*X / (0.21-X)
(1.7x10^-4)*(0.21-X) = X^2      by solving this equation for X
∴X = 0.0059
∴[H+] = 0.0059
∴PH= -㏒ [H+]
       = -㏒ 0.0059
       = 2.23 
        
             
        
        
        
<u>Answer:</u>
<u>For a:</u> The balanced equation is 
<u>For c:</u> The balanced equation is 
<u>Explanation:</u>
A balanced chemical equation is one where all the individual atoms are equal on both sides of the reaction. It follows the law of conservation of mass.
The given unbalanced equation follows:

To balance the equation, we must balance the atoms by adding 2 infront of both  and
 and  and 3 in front of
 and 3 in front of 
For the balanced chemical equation:

The given balanced equation follows:

The given equation is already balanced.
The given unbalanced equation follows:

To balance the equation, we must balance the atoms by adding 2 infront of 
For the balanced chemical equation:
 
 
The given balanced equation follows:

The given equation is already balanced.