Not sure, but I would guess it's due to environmental factors, like heat, and imperfections in the metal. Just an educated guess, though.
 
        
             
        
        
        
Answer: The correct statements are ; A and B.
Explanation:
The strength of the magnetic field(B) in an electromagnet can be calculated using formula:

 = Relative permeability
 = Relative permeability
N = number of turns 
I = Current in the wire of the solenoid
L = length of the solenoid or electromagnetic
As we can see from the formula:


So, by increasing the turns and increasing current flowing through wire one can increase the strength of an electromagnet.
Hence, the correct statements are ; A and B.
 
        
             
        
        
        
Answer:
C) It will accelerate.  
Explanation:
According to Newton’s second law of motion, when an object is acted on by an unbalanced force, it will accelerate.
An unbalanced force will change the speed or direction (or both) of an object. A change in speed and/or direction is acceleration.
A) is wrong. The object will stop moving only if there is a balanced force in the opposite direction.
B) is wrong. The object will decrease speed only if the unbalanced force has a component opposite to the direction of motion.
d) is wrong. The object will increase speed only if the unbalanced force has a component in the direction of motion.
 
        
             
        
        
        
Answer:
220mol.
Explanation:
Water is H2O. Hydrogen gas is H2. Oxygen gas is O2. You have 220mol of O and 460mol of H. O is the limiting reactant. The ratio O:H2O is 1:1. 220*1=220
 
        
             
        
        
        
To ensure that the 9-Fluorenone was totally dry, it had to be washed with methylene chloride. To make sure that methylene chloride is present in a pure solution, sodium sulfate binds to water and precipitates.
<h3>
What is the purpose of the sodium sulfate?</h3>
- Although it has numerous additional uses, sodium sulfate is primarily employed in the production of detergents and in the Kraft process of paper pulping. 
- The decahydrate's natural mineral form, mirabilite, accounts for about half of the world's output, with the other half coming from chemical byproducts. Sodium sulfate was used as a drying, isolating, and anhydrous salt for the 9-fluorenone.
- To make sure that methylene chloride is present in a pure solution, sodium sulfate binds to water and precipitates.
- The sodium salt of sulfuric acid is known as sodium sulfate. Na2SO4 is the chemical formula for sodium sulfate. The mineral thenardite, which is also known as anhydrous sulfate, is described as a white, crystalline solid, whereas the decahydrate Na2SO4. 10H2O is also known as Glauber's salt or the mirabilis salt.
To know more about sodium sulfate, refer:
brainly.com/question/23509646
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