Answer:
two examples are blood and soapy water.
Explanation:
 
        
             
        
        
        
Explanation:
Since HF is a weak acid, the use of an ICE table is required to find the pH. The question gives us the concentration of the HF.
HF+H2O⇌H3O++F−HF+H2O⇌H3O++F−
Initial0.3 M-0 M0 MChange- X-+ X+XEquilibrium0.3 - X-X MX M
Writing the information from the ICE Table in Equation form yields
6.6×10−4=x20.3−x6.6×10−4=x20.3−x
Manipulating the equation to get everything on one side yields
0=x2+6.6×10−4x−1.98×10−40=x2+6.6×10−4x−1.98×10−4
Now this information is plugged into the quadratic formula to give
x=−6.6×10−4±(6.6×10−4)2−4(1)(−1.98×10−4)−−−−−−−−−−−−−−−−−−−−−−−−−−−−√2x=−6.6×10−4±(6.6×10−4)2−4(1)(−1.98×10−4)2
The quadratic formula yields that x=0.013745 and x=-0.014405
However we can rule out x=-0.014405 because there cannot be negative concentrations. Therefore to get the pH we plug the concentration of H3O+ into the equation pH=-log(0.013745) and get pH=1.86
 
        
             
        
        
        
Answer:
Option D. ZnCl₂ and H₂
Explanation:
From the question given above, the following equation was obtained:
2HCl + Zn —> ZnCl₂ + H₂
Products =? 
In a chemical equation, reactants are located on the left side while products are located on the right side i.e
Reactants —> Products
Now, considering the equation from the question i.e
2HCl + Zn —> ZnCl₂ + H₂
The products are ZnCl₂ and H₂ because from our discussion above, we said that products are only located on the right side of chemical equation.
Thus, option D gives the correct answer to the question. 
 
        
             
        
        
        
Answer:
Static Friction.
Explanation:
Friction is the force that resists the relative motion between the surfaces sliding against each other.
Static friction is friction between objects that are not in relative motion with each other.
The coefficient of static friction, typically denoted as  μs,
Static friction arises due to surface roughness( relative term)
The static friction force can be overcome by an applied  maximum force
F max =  μs x N
N= normal force
 Any force smaller than F max attempting to slide one surface over the other is opposed by a frictional force of equal magnitude and opposite direction.
Any force larger than F max overcomes the force of static friction and causes sliding to occur.
This maximum force is sometimes called the limiting value also. Here that value is 75 N.
 
        
             
        
        
        
Try out answer C magnesium oxides melting point is almost 5 times higher than magnesium