Answers AZ-Physical Science A-CRLab: Rate of Chemical Reactions

Lab: Rate of Chemical Reactions — Unit test Answers

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Fluorine has an atomic number 9. It is in period 2 of the periodic table. The diagram shows the electron dot diagram of a fluorine atom.

two

seven

nine

seventeen

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Which element has fewer than four dots in its electron dot diagrams?

arsenic (As)

sulfur (S)

krypton (Kr)

gallium (Ga)

Which is the only element in group 1 on the periodic table that forms covalent bonds?

hydrogen

lithium

potassium

sodium

Formaldehyde is an organic compound. Each molecule includes two hydrogen (H) atoms, one oxygen (O) atom, and one carbon (C) atom. Below are the dot structures for each of these elements.Which diagram shows how the covalent bonds most likely form in a formaldehyde molecule?

Option

Which statement best describes balancing equations and the law of conservation of mass?

There are more atoms in the reactants than in the products, and the total mass is the same in the reactants and in the products.

The number of atoms is the same in the reactants and in the products, and the total mass is the same in the reactants and in the products.

There are fewer atoms in the reactants than in the products, and the total mass is less in the reactants than in the products.

There are more atoms in the reactants than in the products, and the total mass is higher in the reactants than in the products.

The first chart shows the effect of the normal breakdown of material from reactants to products. The second chart shows the same reaction but with an added modification.

Reaction A has an enzyme.

Reaction B has an enzyme.

Reaction A has an inhibitor.

Reaction B has an inhibitor.

What is produced during the replacement reaction of Cu(NO3)2 and Zn?

ZnNO3 + Cu

Zn + Cu(NO3)2

ZnCu + 2NO3

Zn(NO3)2 + Cu

Why do natural polymers not pose as much of an issue in landfills as synthetic polymers?

Natural polymers are cheap to recycle, and synthetic polymers are expensive to recycle.

Natural polymers are expensive to recycle, and synthetic polymers are cheap to recycle.

Natural polymers are not biodegradable, and synthetic polymers are biodegradable.

Natural polymers are biodegradable, and synthetic polymers are not biodegradable.

The element sulfur (S) is most likely to form covalent bonds with the element

helium (He).

magnesium (Mg).

zinc (Zn).

oxygen (O).

How many atoms of each element are in the chemical formula NH4NO3?

1 nitrogen, 1 hydrogen, and 3 oxygen

1 nitrogen, 4 hydrogen, and 3 oxygen

2 nitrogen, 4 hydrogen, and 3 oxygen

5 nitrogen, 1 hydrogen, and 1 oxygen

Eugene works at a carpet factory. Which natural polymer does he most likely work with to make the carpets?

wool

rubber

nylon

silk

How do the nuclei of covalently bonded atoms help keep the bond together?

Neutral particles in the nucleus provide enough mass that the force of gravity holds the atoms together.

Neutral particles in the nucleus can become positive or negative in order to balance the charges.

Positive particles in the nucleus change into negative particles that enter electron shells.

Positive particles in the nucleus are attracted to shared electrons, so the atoms stay close together.

What else is produced during the replacement reaction of magnesium and hydrochloric acid?Mg + 2HCl H2 + ________

MgCl2

Mg2Cl2

Mg2Cl

MgCl

Which element is least likely to form chemical bonds?

phosphorus (P)

helium (He)

sodium (Na)

carbon (C)

Atoms of iron (Fe) form metallic bonds with other iron atoms. How are the valence electrons of these atoms rearranged to form the bonds?

A few valence electrons are shared between the atoms.

Many valence electrons are shared between the atoms.

Electrons are transferred from the iron atoms to atoms in the air.

Electrons are transferred to the iron atoms from atoms in the air.

Mora measures the speed of the particles in a solid mass. She wants to speed up the action. Which action will allow her to do so?

adding more mass

breaking it apart

using an inhibitor

lowering the activation energy

If a chemical reaction does not reach its activation energy, which will most likely occur?

The chemical bonds will remain unchanged.

The chemical bonds will break.

The chemical bonds will have high kinetic energy.

The chemical bonds will already be broken.

Lionel has a hot plate, a thermometer, a container of water, a spoon, and a small hammer. Using these tools, Lionel can test several properties of an ionic compound.Which property of the compound will he not be able to test?

atomic structure

melting point

ability to dissolve

brittleness

When balanced, which equation would have the coefficient 3 in front of any of the reactants?

Zn + HCl ZnCl2 + H2