1.
Χημικό στοιχείο είναι:
Correct Answer
D. το άζωτο.
Explanation
The correct answer is "το άζωτο" because it is the only option that is not a common substance found in water. Water (νερό), salt (αλάτι), and sugar (ζάχαρη) can all dissolve in water, but nitrogen (άζωτο) is an element that does not typically dissolve in water.
2.
Χημική ένωση είναι:
Correct Answer
C. το διοξείδιο του άνθρακα.
Explanation
The correct answer is "το διοξείδιο του άνθρακα" because it is the only option that refers to carbon dioxide. The other options, "το οξυγόνο," "το υδρογόνο," and "ο άνθρακα," do not specifically mention carbon dioxide.
3.
Τα όμοια άτομα όταν ενώνονται δημιουργούν:
Correct Answer
B. μόρια χημικών στοιχείων.
Explanation
The question is asking for the unit of measurement for chemical elements. The correct answer is "μόρια χημικών στοιχείων" which translates to "moles of chemical elements." Moles are used to measure the amount of a substance, and in the context of chemistry, it is commonly used to measure the amount of atoms or molecules present in a sample. Therefore, the correct answer refers to the unit of measurement for chemical elements.
4.
Τα μόρια των χημικών ενώσεων αποτελούνται από:
Correct Answer
B. διαφορετικά άτομα.
Explanation
The correct answer is "διαφορετικά άτομα" because the question is asking for a phrase that means "different individuals." The other options do not accurately convey this meaning. "Διαφορετικά μόρια" means "different molecules," "όμοια άτομα" means "similar individuals," and "άτομα και μόρια" means "individuals and molecules." Therefore, "διαφορετικά άτομα" is the most appropriate answer.
5.
Με Ν συμβολίζεται το στοιχείο:
Correct Answer
B. άζωτο.
Explanation
The correct answer is "άζωτο" because it is the Greek word for nitrogen. The question is asking for the translation of the word "nitrogen" into Greek, and "άζωτο" is the correct translation.
6.
Με Fe συμβολίζεται το στοιχείο:
Correct Answer
A. σίδηρος.
7.
Με Ca συμβολίζεται το στοιχείο:
Correct Answer
C. ασβέστιο.
Explanation
The correct answer is ασβέστιο because it is the Greek word for "calcium". The question asks for the Greek translation of "calcium" and ασβέστιο is the correct translation.
8.
Ποιο από τα παρακάτω συμβολίζει χημικό στοιχείο;
Correct Answer
C. Na.
Explanation
The correct answer is Na. Na is the chemical symbol for sodium, which is a highly reactive metal. It is commonly found in compounds such as sodium chloride (NaCl) and is an essential element for many biological processes in the body. Sodium is also important in various industrial applications, such as in the production of glass and soap.
9.
Ποιο από τα παρακάτω συμβολίζει χημική ένωση;
Correct Answer
A. NaF.
Explanation
The correct answer is NaF because NaF is the chemical formula for sodium fluoride. Sodium fluoride is a compound commonly used in toothpaste and water fluoridation to prevent tooth decay. Na, Fe, and Ba are the chemical symbols for sodium, iron, and barium, respectively, but they do not form the correct compound with fluorine.
10.
1 μόριο της χημικής ένωσης ΝΗ3 αποτελείται από:
Correct Answer
C. 3 άτομα υδρογόνου.
Explanation
The question asks for the correct formula for sodium hydroxide. The correct answer is "3 άτομα υδρογόνου" which translates to "3 hydrogen atoms" in English. This is the correct formula for sodium hydroxide, which consists of one sodium atom, one oxygen atom, and three hydrogen atoms.