2NaCN(s) + H₂SO₄(aq) --> Na₂SO₄(aq) + 2HCN(g)  
The molar ratio between NaCN : HCN is 2:2  or 1:1
Mass of HCN = 16.7 g
Molar mass of HCN = 1 + 12 + 14 = 27 g/mol
Molar mass of NaCN = 49 g/mol
Therefore, the mass of NaCN is 
16.7 g of  HCN x 49 g/mol of NaCN / 27 g/mol of HCN = 30.3 grams of NaCN 
Therefore, 30.3 grams of NaCN gives the lethal dose in the room. 
 
        
                    
             
        
        
        
Answer:
Helps eliminate waste products such as urea, uric acid ammonia, and other products via urine.
It helps maintain the osmotic level of blood and plasma.
It helps maintain the electrolyte balance in the body.
And it also helps in the metabolism of those drugs that do not get metabolized in the liver.
Explanation:
<em>"The excretory system is a passive biological system that removes excess, unnecessary materials from the body fluids of an organism, so as to help maintain internal chemical homeostasis and prevent damage to the body. The dual function of excretory systems is the elimination of the waste products of metabolism and to drain the body of used up and broken down components in a liquid and gaseous state"</em>
 
        
             
        
        
        
While there is no such thing as 100 percent safe, having nuclear energy is much safer than you think. It's thousands of times safer than conventional coal and other fossil-fuel-derived energy, not to mention the specter of environmental disaster from continued use of carbon-based energy sources.
        
             
        
        
        
So there are basically five types of chemical reactions which have their general formulas. 
They are:
1. Combination reaction 
 General formula : A+B = AB
2. Decomposition reaction
 General formula: AB = A+B
3. Single displacement reaction
 General formula: AB+C = CB + A
4. Double displacement reaction
 General formula: AB+CD = CB+AD
5. Acid-base reaction
 General formula: A+B = S+W
You should check and compare with examples.
        
             
        
        
        
Answer:
A. The pressure will increase 4 times. P₂ = 4 P₁
B. The pressure will decrease to half its value. P₂ = 0.5 P₁
C. The pressure will decrease to half its value. P₂ = 0.5 P₁
Explanation:
Initially, we have n₁ moles of a gas that occupy a volume V₁ at temperature T₁ and pressure P₁.
<em>What would happen to the gas pressure inside the cylinder if you do the following?</em>
<em />
<em>Part A: Decrease the volume to one-fourth the original volume while holding the temperature constant. Express your answer in terms of the variable P initial.</em>
V₂ = 0.25 V₁. According to Boyle's law,
P₁ . V₁ = P₂ . V₂
P₁ . V₁ = P₂ . 0.25 V₁
P₁ = P₂ . 0.25
P₂ = 4 P₁
<em>Part B: Reduce the Kelvin temperature to half its original value while holding the volume constant. Express your answer in terms of the variable P initial.</em>
T₂ = 0.5 T₁. According to Gay-Lussac's law,

<em>Part C: Reduce the amount of gas to half while keeping the volume and temperature constant. Express your answer in terms of the variable P initial.</em>
n₂ = 0.5 n₁.
P₁ in terms of the ideal gas equation is:

P₂ in terms of the ideal gas equation is:
