Homework - Y7 W1 - Chemical reactions

Homework - Chemical reactions & physical changes.

What is the process in which one or more substances are changed into one or more different substances?

1. Combustion
2. Chemical reaction
3. Physical reaction
4. Biological reaction

Which of the following is an example of a chemical reaction?

1. Mixing salt in water
2. Boiling water
3. Burning of wood
4. Melting of ice

In a chemical reaction, what are the substances present at the beginning called?

1. Reactants
2. Catalysts
3. Products
4. Inhibitors

In a chemical reaction, what are the substances at the end of the reaction called?

1. Reactants
2. Catalysts
3. Products
4. Inhibitors

What is the process in which one or more substances are changed into one or more different substances?

1. Combustion
2. Chemical reaction
3. Physical reaction
4. Biological reaction

The start of the reaction the chemicals are called...

1. Products
2. Reactants

What does not change during a chemical reaction

1. The products made
2. The total number of products
3. The total number of atoms each element
4. The total number of reactants.

The end of the reaction the chemicals are called...

1. Products
2. Reactants

What factors can affect the rate of a chemical reaction?

1. Temperature
2. Volume
3. Concentration
4. Surface Area

What is the process of rearranging atoms in a substance called?

1. Molecular transformation
2. Chemical reaction
3. Atomic shuffling
4. Elemental reorganization

What happens to the rate of a chemical reaction when the temperature is increased?

1. The rate of reaction decreases
2. The rate of reaction remains the same
3. The rate of reaction becomes unpredictable
4. The rate of reaction increases

In a chemical reaction, what does the conservation of mass imply about the total mass of the reactants and products?

1. It doubles
2. It remains the same
3. It quadruples
4. It halves

Which of the following is a physical change?

1. Boiling water
2. Melting ice
3. Rusting iron
4. Burning wood

What happens to the chemical composition during a physical change?

1. It changes completely
2. It remains the same

Which of the following is an example of a physical change in matter?

1. Mixing salt and water
2. Burning paper
3. Digesting food

What is the state of matter changes in a physical change?

1. The state remains constant
2. The state may change

Which of the following describes a physical change?

1. Change in size
2. Change in shape
3. Change in color
4. Change in odor

Which enzyme is used in the COVID tests to turn RNA into DNA

1. Transcriptase
2. Tripase
3. Triptilase
4. Reverse transcriptase

By repeatedly heating and cooling DNA with a primer, the DNA building enzyme makes millions of copies of

1. Cell DNA
2. Host DNA
3. Virus DNA
4. Primer

Fluorescent dye molecules bind to the virus DNA as it is copied. Binding them makes them give off more light, which is used to....

1. Confirm the presence of the virus
2. Confirm the absence of the virus

Tests which are in development are looking for

1. Proteins on the surface of the bacteria
2. Proteins on the surface of the protist
3. Proteins on the surface of the virus
4. Proteins on the surface of the fungi