Chemistry Exam 1 (Chapters 1-4)
Approved Answers for Chemistry
Exam 1
What is a scientific hypothesis?
✓✓ A scientific hypothesis is a testable explanation or prediction based on observations.
What is an observation in chemistry?
✓✓ An observation is information gathered using the senses or measuring instruments during
an investigation.
What is an experiment?
✓✓ An experiment is a controlled procedure used to test a hypothesis.
What is a conclusion in the scientific method?
✓✓ A conclusion is a statement that explains whether the experimental results support the
hypothesis.
What is the difference between qualitative and quantitative observations?
✓✓ Qualitative observations describe qualities without numbers, while quantitative
observations involve numerical measurements.
What is the SI unit of temperature?
✓✓ The SI unit of temperature is the kelvin (K).
How is temperature in kelvin obtained from degrees Celsius?
✓✓ Temperature in kelvin is obtained by adding 273.15 to the temperature in degrees Celsius.
What instrument is commonly used to measure mass in a laboratory?
✓✓ A laboratory balance is commonly used to measure mass.
What instrument is used to measure the volume of a liquid accurately?
✓✓ A graduated cylinder is used to measure the volume of a liquid accurately.
Why should measurements be recorded with the correct units?
✓✓ Correct units ensure accuracy, consistency, and clear communication of scientific results.
, What are significant figures?
✓✓ Significant figures are the digits in a measurement that include all certain digits and one
estimated digit.
Why are significant figures important in chemistry?
✓✓ They indicate the precision and reliability of measured values.
What is precision in scientific measurements?
✓✓ Precision is the closeness of repeated measurements to one another.
What is accuracy in scientific measurements?
✓✓ Accuracy is the closeness of a measured value to the true or accepted value.
What is an ion?
✓✓ An ion is an atom or group of atoms that has gained or lost electrons and therefore carries a
net electrical charge.
How is a positive ion formed?
✓✓ A positive ion is formed when an atom loses one or more electrons.
How is a negative ion formed?
✓✓ A negative ion is formed when an atom gains one or more electrons.
What is the difference between an atom and an ion?
✓✓ An atom has equal numbers of protons and electrons, while an ion has unequal numbers of
protons and electrons, giving it a net charge.
Why do atoms form chemical bonds?
✓✓ Atoms form chemical bonds to achieve a more stable electron arrangement.
What is a chemical formula?
✓✓ A chemical formula is a symbolic representation showing the types and numbers of atoms
present in a compound.
What is chemistry?
✓✓ Chemistry is the branch of science that studies matter, its composition, properties, and the
changes it undergoes.
Approved Answers for Chemistry
Exam 1
What is a scientific hypothesis?
✓✓ A scientific hypothesis is a testable explanation or prediction based on observations.
What is an observation in chemistry?
✓✓ An observation is information gathered using the senses or measuring instruments during
an investigation.
What is an experiment?
✓✓ An experiment is a controlled procedure used to test a hypothesis.
What is a conclusion in the scientific method?
✓✓ A conclusion is a statement that explains whether the experimental results support the
hypothesis.
What is the difference between qualitative and quantitative observations?
✓✓ Qualitative observations describe qualities without numbers, while quantitative
observations involve numerical measurements.
What is the SI unit of temperature?
✓✓ The SI unit of temperature is the kelvin (K).
How is temperature in kelvin obtained from degrees Celsius?
✓✓ Temperature in kelvin is obtained by adding 273.15 to the temperature in degrees Celsius.
What instrument is commonly used to measure mass in a laboratory?
✓✓ A laboratory balance is commonly used to measure mass.
What instrument is used to measure the volume of a liquid accurately?
✓✓ A graduated cylinder is used to measure the volume of a liquid accurately.
Why should measurements be recorded with the correct units?
✓✓ Correct units ensure accuracy, consistency, and clear communication of scientific results.
, What are significant figures?
✓✓ Significant figures are the digits in a measurement that include all certain digits and one
estimated digit.
Why are significant figures important in chemistry?
✓✓ They indicate the precision and reliability of measured values.
What is precision in scientific measurements?
✓✓ Precision is the closeness of repeated measurements to one another.
What is accuracy in scientific measurements?
✓✓ Accuracy is the closeness of a measured value to the true or accepted value.
What is an ion?
✓✓ An ion is an atom or group of atoms that has gained or lost electrons and therefore carries a
net electrical charge.
How is a positive ion formed?
✓✓ A positive ion is formed when an atom loses one or more electrons.
How is a negative ion formed?
✓✓ A negative ion is formed when an atom gains one or more electrons.
What is the difference between an atom and an ion?
✓✓ An atom has equal numbers of protons and electrons, while an ion has unequal numbers of
protons and electrons, giving it a net charge.
Why do atoms form chemical bonds?
✓✓ Atoms form chemical bonds to achieve a more stable electron arrangement.
What is a chemical formula?
✓✓ A chemical formula is a symbolic representation showing the types and numbers of atoms
present in a compound.
What is chemistry?
✓✓ Chemistry is the branch of science that studies matter, its composition, properties, and the
changes it undergoes.
