Let's analyze the chemical formula for sodium citrate, which is [tex]\( \text{Na}_3 \text{C}_6 \text{H}_5 \text{O}_7 \)[/tex].
1. Identify the elements and their quantities:
- Sodium (Na): 3 atoms
- Carbon (C): 6 atoms
- Hydrogen (H): 5 atoms
- Oxygen (O): 7 atoms
2. Sum the number of atoms:
- [tex]\( 3 \text{ (sodium atoms)} + 6 \text{ (carbon atoms)} + 5 \text{ (hydrogen atoms)} + 7 \text{ (oxygen atoms)} = 21 \text{ atoms} \)[/tex]
3. Classify the substance:
- Sodium citrate is a compound because it consists of multiple elements chemically bonded together.
- An element consists of only one type of atom, whereas a compound consists of two or more different types of atoms.
4. Evaluate the statements:
- Statement A: "Sodium citrate is a compound with a total of 21 atoms." This statement is true because the total number of atoms in sodium citrate is 21.
- Statement B: "Sodium citrate is a compound with a total of 4 atoms." This statement is false because the total number of atoms is 21, not 4.
- Statement C: "Sodium citrate is an element with a total of 21 atoms." This statement is false because sodium citrate is a compound, not an element.
- Statement D: "Sodium citrate is a compound with a total of 21 atoms, each of a different element." This statement is false because there are only 4 different types of atoms (sodium, carbon, hydrogen, and oxygen), not 21 different types.
Therefore, the true statement is:
Sodium citrate is a compound with a total of 21 atoms.
