<u>Answer:</u> The true statement is iron can reduce 
to gold metal
<u>Explanation:</u>
Single displacement reaction is defined as the reaction in which more reactive element displaces a less reactive element from its chemical reaction.
The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.
Metal A is more reactive than metal B.
We are given:
Iron can reduce copper, silver can reduce gold, sodium can reduce iron and copper can reduce silver metal.
The increasing order of reactivity thus follows:
where, sodium is most reactive and gold is least reactive
For the given options:
<u>Option 1:</u> Copper cannot easily reduce sodium ion to sodium metal because it is less reactive.
<u>Option 2:</u> Iron cant easily reduce gold ion to gold metal because it is more reactive.
<u>Option 3:</u> Silver cannot easily reduce iron ion to iron metal because it is less reactive.
Hence, the true statement is iron can reduce to gold metal
Adding and subtracting with scientific notation may require more care, because the rule for adding and subtracting exponential expressions is that the expressions must havelike terms<span>. Remember that to be </span>like terms<span>, two expressions must have exactly the same base numbers to exactly the same powers. Thinking about decimal arithmetic, the requirement that we have the same powers makes sense, because that guarantees that all of the place values are lined up properly.</span>
Double replacement :
2Na₃PO₄+3CaCl₂⇒6NaCl + Ca₃(PO₄)₂
<h3>Further explanation</h3>
1. A single replacement reaction is a chemical reaction in which one element replaces the other elements of a compound to produce new elements and compounds
2. Double-Replacement reactions. Happens if there is an ion exchange between two ion compounds in the reactant to form two new ion compounds in the product
3. Combination/syntesis : 2 or more reactants combine to form a new compound
4. Decomposition : the reactant is decomposed into 2/more products
If we look at the reaction options available, all of them can be included in the double replacement reaction, but we only choose the reaction from Sodium phosphate and Calcium chloride which leads to options: C because it is balanced (from the number of atoms in the same reactant and product) and is in accordance with the chemical formula of each compound (both products and reactants)
Answer:
The correct answer is option 3. Run a test reaction of crude oil with ocean water over time with Oil Spill Eater present
Explanation:
In any laboratory experiment, all the apparatus needed to carry out a particular experiment must be provided. In this case, our apparatus will be crude oil with ocean water and oil spill eater which is the enzyme used.
We can then run a test reaction of crude oil with ocean water over time with Oil Spill Eater present.
