HESI Chemistry Practice Test 1

Question 1

What is the atomic number of an unknown element with 45 protons and an atomic mass of 64?

Accepted Answer

45

Answer

The atomic number of an element is defined by the number of protons in the nucleus of an atom. Since the unknown element has 45 protons, its atomic number is 45. The atomic mass, which is the sum of protons and neutrons, does not change the atomic number itself.

Question 2

What is the usage of scientific notation?

Accepted Answer

The plan is to make it easier to deal with both tiny and large quantities.

Answer

Scientific notation is a mathematical tool used to express very large or very small numbers in a more concise and manageable form. By representing numbers as a product of a coefficient and a power of 10, it simplifies calculations and comparisons involving extreme magnitudes, making them easier to read and understand.

Question 3

In degrees Celsius, a typical human body temperature is

Accepted Answer

37 degrees

Answer

The typical normal human body temperature is approximately 37 degrees Celsius (or 98.6 degrees Fahrenheit). This is the average temperature at which the body's metabolic processes function optimally. Slight variations can occur, but 37°C is the widely accepted standard.

Question 4

What is the sodium charge in the compound NaCl?

Accepted Answer

+1

Answer

In the ionic compound NaCl (sodium chloride), sodium (Na) is an alkali metal in Group 1 of the periodic table, meaning it readily loses one electron to achieve a stable electron configuration. When sodium loses an electron, it forms a cation with a charge of +1 (Na+).

Question 5

Which of the following causes cramps during strenuous exercise?

Accepted Answer

Lactate

Answer

During strenuous exercise, when oxygen supply to muscles is insufficient, cells switch to anaerobic respiration, producing lactate (lactic acid) as a byproduct. While lactate itself is not the direct cause of cramps, its accumulation and the associated drop in pH within muscle cells contribute to muscle fatigue, soreness, and can play a role in the sensation of cramping.

HESI (ATI) Practice Test

HESI (ATI) Practice Test

HESI Chemistry Practice Test 1