science unit 1 grade 9
Which set of coefficients will balance this chemical equation? __C2H4(g) + __O2(g) → 2CO2(g) + 2H2O(g)
1 , 3
If 100 grams of vinegar and 5 grams of baking soda are poured in a container, a small amount of gas will be produced. What will the final mass of the products be if the gas is trapped in the container?
105 grams
How many atoms are in one formula unit of the compound FeC5O5?
11
What coefficient for O2 demonstrates the law of conservation of mass? CH4(g) + __O2(g) → CO2(g) + 2H2O(g)
2
The compound potassium sulfate, K2SO4 , is composed of
2 atoms of potassium, 1 atom of sulfur, and 4 atoms of oxygen.
Which set of coefficients will balance this chemical equation? __PbS(s) + __O2(g) → 2PbO(s) + 2SO2(g)
2, 3
Juan Carlos placed 35 grams of ice into a dry, 200-gram container. The top of the container was attached tightly. When the ice was completely melted, the student measured the mass of the container with the liquid water. What should the mass of the liquid water in the container be?
35 grams
A scientist placed a sample of lithium into a container of water. The scientist observed the lithium floating and making a buzzing sound as gas bubbles were forming around it. Which conclusion is BEST supported by this observation?
A chemical change took place.
A student performs an experiment and the results are shown below.Before: Iron filings are brown, small, and magnetic; copper sulfate crystals are blue, brittle, and not magnetic.After: The copper formed was reddish, solid, and not magnetic; iron sulfide solution was colorless and not magnetic.Which statement supports that a chemical reaction took place?
A new substance was formed.
What was observed that led to the arrangement of sixty-three already-known elements by increasing atomic weights in the periodic table?
A repetition occurs in chemical and physical properties.
Which is a compound?
Ammonia (NH3)
A science class is studying the states of matter. One group of students freezes 100 grams (g) of water in a cup. Another group of students melts 50 g of ice in a cup. Which of these will MOST likely occur at the end of the experiment?
Both groups will have the same mass with which they started.
Which statement BEST describes the organization of the periodic table of the elements?
Elements within a group have similar properties.
Which of the following is a correctly written chemical equation that demonstrates the conservation of mass?
H2O + CO2 --> H2CO3
Which of these does NOT illustrate substances reacting to form new substances?
H2O(1) --- H2O(g)
A group of students observed the formation of bubbles when water boiled. What happened to matter because of the physical change to the water?
Matter was conserved when it changed form.
Which of these is an element?
O2
The chemical equation below shows reactants and products. 6CO2 + 12H2O + light + enzymes --> C6H12O6 + 6O2 + 6H2O Which statement is BEST supported by analyzing this equation?
The atoms rearrange in the chemical reaction so that C6H12O6, glucose is made.
A chemical reaction separates water into hydrogen gas and oxygen gas. Which of the following statements is true about the mass of the water and the combined mass of the two gases?
The combined mass of the two gases is the same as the mass of the water.
Which of these is one similarity of the elements in the first group of the periodic table?
The elements in the group react with oxygen in similar ways.
Sodium sulfate and barium chloride react with each other to form sodium chloride and barium sulfate as shown. Which statement MOST accurately describes the mass of the reactants compared to the mass of the products?
The mass of the reactants is the same as the mass of the products.
A student is testing a solid material to determine whether it is a pure substance or a mixture. Which observation would MOST likely indicate that the material is a mixture?
The material has crystals of two different colors.
How does the concept of conservation of mass apply to chemical reactions?
The reactants and products have exactly the same atoms.
A student kept a notebook during an investigation. Which recorded observation was MOST likely a physical change?
The solution was heated for two minutes until it boiled.
When a mixture of oxygen and hydrogen is ignited in a test tube, the reaction shown occurs. Hydrogen + Oxygen --> Water + Energy What happens to the total mass of the contents of the test tube?
The total mass remains the same.
Which is a physical change?
a sheet of paper shredding.
Scientists can identify an element by looking at the structure of a single
atom.
The smallest part of an element that retains the properties of the element is the
atom.
When a molecule is separated into its component parts, it forms
atoms.
Why is photosynthesis a chemical reaction?
because new substances are formed.
When iron combines with oxygen in a moist environment, rust forms because of a
chemical reaction.
Structural differences between different chemicals can be represented in models of the particles. Which drawing BEST represents a compound?
compound image
Which of these are broken down during chemical, but not physical, changes?
compounds
What is needed to change ice into water?
energy
What physical property is characteristic of all of the elements in the group located in the rightmost column of the periodic table?
gas state at room temperature
Based on the information in the table, which mineral is also an element?
graphite
Elements in the same column of the periodic table of the elements all
have similar physical characteristics.
Separating carbon dioxide from a solution of carbonated water is MOST rapidly accomplished by
increasing the temperature of the carbonated water and decreasing the pressure above the surface of the carbonated water.
What is the name of the product formed from the reaction shown below? 4F(III)+3O2 --> 2FE2O3
iron (III) oxide
Which task in the kitchen is an example of a physical change?
melting butter
Which type of matter can be separated by physical means?
mixture
Which characteristic of an element determines its placement in the periodic table?
number of protons
John and Lisa collected a sample of ocean water and placed it in a jar. Within a couple of days, the water had evaporated and salt was visible at the bottom of the jar. This is an example of a
physical change.
Which compound does NOT contain individual molecules?
salt
Elements in the periodic table of the elements are organized into columns and rows.
similarities of the reactivity in groups.
Which of the samples shown represents an element?
substance 2
Where are the most reactive metals located on the periodic table?
the column at the far left side of the table
A beaker contains a sample of water with a mass of 325 grams. The water in the beaker is boiled and weighed again after it cools. The new mass of the water is 305 grams. In this example of the conservation of matter in physical changes?
the mass of the water was 305 grams and the mass of the water vapor was 20 grams.
A flat piece of paper has a mass of 5 grams. When the paper is crumpled into a ball, the mass of the crumpled paper is
the same as that of the flat paper.
Where are the most reactive nonmetals located on the periodic table?
the second column from the right side of the table
