In a single displacement / replacement reaction a single uncombined element replaces another element in a compound.
Single replacement is type of chemical reaction where an element react with a compound and take the place of another element in that compound.
example of this type of reaction is
Zn+ 2HCl -----> Zncl2 + H2
statement about enzymes that is correct is
b. they are large molecules that increase the rate of biologically important reactions
Enzymes are proteins that catalyse, in other words increase the rate of the biological reactions.
Biological functions that are vital for the bodies to survive, have large activation energy barriers. For this reason enzymes are used that reduce the activation energy required for the reaction to initiate. this enables the reactions to proceed.
Substrates bind to the enzyme, reaction occurs and substrate converts to products, that are released from the enzyme, leaving the enzyme unchanged.
so the correct answer is B.
Answer: 0.185 L
Explanation:
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,

where,
= initial pressure of gas = 0.98 atm
= final pressure of gas = 1 atm (at STP)
= initial volume of gas = 0.165 L
= final volume of gas = ?
= initial temperature of gas = 
= final temperature of gas =
(at STP)
Now put all the given values in the above equation, we get:


Thus the volume of this gas at STP be 0.185 L
Group 17 is the most readily reduced elements on the periodic table, meaning that they are so close to being a stable elements, only missing 1 electron to complete their valance electron shell. Thus they will essentially react with anything to get that last electron!
Group 1 elements are extremely reactive because they are the most readily oxidized, they are very close to reaching stability by giving up only 1 electron. Thus they will react with almost anything to give up their electron.
Answer:
a b d
these are part of an ecosystem or can be