Question 1

The juice from an orange is a mixture.

Accepted Answer

The juice from an orange is a mixture of water, sugars, acids, and other compounds.

Question 2

The number 6.0448,rounded to 3 decimal places,becomes 6.045.

Accepted Answer

When rounding to 3 decimal places, we look at the 4th digit after the decimal point. If it is 5 or above, we round up the 3rd digit. In this case, the 4th digit is 8 which is greater than 5, so we round up the 3rd digit from 4 to 5. Therefore, 6.0448 rounded to 3 decimal places becomes 6.045.

Question 3

The ripening of fruit,once picked,is an example of physical change.

Accepted Answer

The ripening of fruit involves chemical changes, including the conversion of starches to sugars, changes in color, and the breakdown of cell walls, which are not reversible and alter the chemical composition of the fruit.

Question 4

When applying the scientific method,a model or theory should be based on experimental data.

Accepted Answer

The scientific method involves formulating a hypothesis or a model based on observations, and then testing it through experiments or other empirical methods. The data obtained from these experiments is used to validate or refine the model or theory, and to make predictions about future observations. Therefore, a model or theory should be based on experimental data in order to be scientific and accurate.

Question 5

Zero kelvin 0 K < 0°F < 0°C.

Accepted Answer

Zero Kelvin (0 K) is absolute zero, the lowest possible temperature where nothing could be colder and no heat energy remains in a substance. It is equivalent to -273.15°C or -459.67°F. Therefore, 0 K is less than 0°F, which in turn is less than 0°C.

Question 6

A laboratory technician analyzed a sample three times for percent iron and got the following results: 22.43% Fe,24.98% Fe,and 21.02% Fe.The actual percent iron in the sample was 22.81%.The analyst's

Accepted Answer

The analyst's precision was poor because the three results are quite different from each other, but the average of the three results is very close to the actual percent iron in the sample, indicating that the analyst's work was accurate.

Question 7

The rusting of a piece of iron under environmental conditions is a physical change.

Accepted Answer

Rusting of iron is a chemical change, as it involves the reaction of iron with oxygen and water to form hydrated iron (III) oxide, also known as rust. In this process, the chemical composition of the iron changes, making it a chemical change.

Question 8

Walking fast can consume 5.0 kcal per minute.How many hours of exercise are required to consume 450 kcal,the energy in a large candy bar?

Accepted Answer

To burn 450 kcal at a rate of 5.0 kcal per minute, we have:
450 kcal ÷ 5.0 kcal/min = 90 min
Therefore, we need to exercise for 1.5 hours (90 min ÷ 60 min/hr = 1.5 hr) to consume the energy in a large candy bar. The correct answer is D.

Question 9

77 K is colder than 4 K.

Accepted Answer

4 K is a lower temperature than 77 K, therefore 77 K cannot be colder than 4 K.

Question 10

There are 58 counties in California and about 660,000 people in each county.How many million people live in California?

Accepted Answer

To find the total population of California, we need to multiply the number of counties by the population per county.

58 counties x 660,000 people per county = 38,280,000 people

Therefore, the answer is B, 38 million people.

Question 11

Which of the following represents the greatest mass?

Accepted Answer

The answer of Which of the following represents the greatest...

Question 12

When applying the scientific method,it is important to avoid any form of hypothesis.

Accepted Answer

It is important to formulate a hypothesis when applying the scientific method. The scientific method involves forming a hypothesis, testing it through experimentation or observation, analyzing the data, and drawing conclusions based on the results.

Question 13

A particular temperature in degrees Celsius is larger than the temperature in kelvins.

Accepted Answer

It is not possible for a temperature in Celsius to be larger than the temperature in Kelvin as they have different reference points. The lowest possible temperature in Kelvin is 0 K, which is equivalent to -273.15°C, so any temperature in Celsius will always be larger than its Kelvin equivalent.

Question 14

The density of a substance is an intensive property.

Accepted Answer

Density is an intensive property, which means it does not depend on the amount or size of the substance, but rather on its composition and structure.

Question 15

Boiling point and melting point are extensive properties.

Accepted Answer

Boiling point and melting point are intensive properties because they do not depend on the amount of substance present.

Question 16

The volume of a substance is an intensive property.

Accepted Answer

The volume of a substance is a extensive property, which means it depends on the amount (or size) of the substance being considered. Intensive properties, on the other hand, do not depend on the amount of the substance and are characteristic of the substance itself, such as density, temperature, and pressure.

Question 17

Matter is anything that has mass and occupies space.

Accepted Answer

Matter is defined as anything that has mass and takes up space, so this statement is true.

Question 18

____________ tells how close a measurement is to the true value.

Accepted Answer

The answer of ____________ tells how close a measurement is...

Question 19

The density of magnesium is 1.7 g/cm³,and the density of iron is 7.9 g/cm³.Consider a block of iron with a mass of 819 g.What is the mass of a block of magnesium that has the same volume as the block of iron?

Accepted Answer

The mass of the magnesium block can be calculated using the formula: mass = density * volume. Since the volume of the magnesium block is the same as that of the iron block, we can use the density of iron to calculate the volume: volume = mass / density = 819 g / 7.9 g/cm³ = 104 cm³. Now we can use the density of magnesium to calculate the mass of the magnesium block: mass = density * volume = 1.7 g/cm³ * 104 cm³ = 176.8 g.

Question 20

A scoop of vanilla ice cream is a pure substance.

Accepted Answer

A scoop of vanilla ice cream is not a pure substance as it is composed of various components such as cream, sugar, vanilla extract, and other ingredients.

Quiz 1: Chemistry: the Central Science