80 Questions
Which of the following is an example of a chemical change?
Rusting of an almirah
What is the key difference between an element and a compound?
Elements are made up of only one type of atom, while compounds are made up of two or more types of atoms.
Which of the following is an example of a metalloid?
Silicon
What type of change occurs when electric current is passed through water, causing it to break down into hydrogen and oxygen gases?
Chemical change
Which of the following is NOT a property of metals?
Ability to easily break apart
Which salt has the highest solubility at a given temperature?
Potassium nitrate
What is the effect of increasing temperature on the solubility of a salt?
Solubility increases
Which of the following is an example of a saturated solution?
A solution containing the maximum amount of dissolved solute at a given temperature
Which of the following is an example of a chemical change?
Rusting of iron
Which of the following is an example of a homogeneous mixture?
Soda water
Which of the following is NOT a physical property of matter?
Flammability
What type of change occurs when a substance undergoes a chemical reaction?
Chemical change
Which of the following is an example of a physical change?
Melting of ice
In the given table, which type of colloid is represented by milk?
Emulsion
Which of the following statements about the interconversion of states is true?
It is a physical change because the composition remains the same.
Which statement is correct about the mixture obtained by Group I?
Its properties are the same as those of its constituents
What is the key difference between the materials obtained by Group I and Group II?
All of the above
What is the meaning of the term 'variable composition' in the context of mixtures?
The composition of a mixture can change depending on the proportions of its constituents
Which of the following statements is true about the compound obtained by Group II?
It has different properties compared to its constituent elements
What is the significance of the observation that the texture and color of the compound obtained by Group II are the same throughout?
It indicates that the compound is a pure substance with a fixed composition
Which separation technique would be most appropriate for separating ammonium chloride from a mixture containing sodium chloride and ammonium chloride?
Differential solubility
If Pragya makes a saturated solution of potassium chloride in water at 353 K and allows it to cool to room temperature (293 K), what would she observe?
The solute would precipitate out of the solution.
If the solubility of potassium nitrate at 313 K is 62 grams per 100 grams of water, what mass of potassium nitrate would be needed to produce a saturated solution in 50 grams of water at the same temperature?
31 grams
Which of the following changes involves a chemical reaction?
Electrolysis of water
Based on the solubility data provided, which salt exhibits the least change in solubility over the given temperature range?
Sodium chloride
Which statement best describes a physical change?
A change in the physical state or appearance of a substance without altering its chemical composition
If a compound is formed from two elements A and B, which of the following statements is true?
The properties of the compound are different from the properties of elements A and B
Which of the following statements about chemical reactions is incorrect?
Chemical reactions can only occur between compounds, not elements
What is the major difference between a solution and a suspension?
A solution is homogeneous, while a suspension is heterogeneous
Which of the following statements about colloids is correct?
Colloids are heterogeneous mixtures in which the particle size is small enough to scatter light but too large to be seen with the naked eye
Which of the following mixtures is classified as a heterogeneous mixture?
A mixture of chalk powder and wheat flour
Which of the following represents a physical change?
Dissolving sugar in water
What type of mixture is formed when a few drops of milk are added to water?
Heterogeneous mixture
Which of the following represents a chemical change?
Decomposition of calcium carbonate on heating
In the given activity, which group is most likely to form a homogeneous mixture?
Group A (50 mL water + 1 spatula copper sulfate)
Which of the following represents a change in the state of matter?
Melting of ice
Which of the following mixtures can be separated by physical means, such as filtration or evaporation?
A solution of salt dissolved in water
Which of the following represents a chemical property of matter?
The ability to undergo combustion
In the given activity, which group is most likely to form a heterogeneous mixture with a non-uniform appearance?
Group C (chalk powder or wheat flour)
Which of the following represents a chemical reaction?
Burning of natural gas
List three properties that metals typically exhibit.
Malleability, sonorousness, lustrousness
Identify the only metal that is liquid at room temperature.
Mercury
What are metalloids and provide two examples?
Elements with intermediate properties between metals and nonmetals; Boron, Silicon
List three properties that are typically exhibited by non-metals.
Variety of colors, poor conductors of heat and electricity, not lustrous
How many naturally occurring elements are there, and how many elements are man-made?
92 naturally occurring elements, rest are man-made
Which group obtained a material with magnetic properties?
Group I
Can we separate the components of the material obtained by the two groups?
Yes
On adding dilute sulphuric acid or dilute hydrochloric acid, did both the groups obtain a gas?
Yes
Did the gas obtained in both cases smell the same or different?
Different
What is the key difference between an element and a compound?
Elements are made of only one type of atom, while compounds are made of two or more different elements chemically bonded together.
What is the major difference between a mixture and a compound?
A mixture has a variable composition and can be separated easily by physical methods, whereas a compound has a fixed composition and can only be separated by chemical or electrochemical reactions.
Explain the properties of a compound compared to its constituent elements.
A compound has a fixed composition throughout, with properties different from the elements that form it.
What are the characteristics of metals and metalloids?
Metals are typically shiny, malleable, and good conductors of heat and electricity, while metalloids exhibit properties intermediate between metals and non-metals.
How can non-metals be distinguished from metals?
Non-metals are generally not shiny, poor conductors of heat and electricity, and brittle in nature.
Describe the key differences between a homogeneous mixture and a heterogeneous mixture.
A homogeneous mixture has a uniform appearance and composition throughout, while a heterogeneous mixture has non-uniform appearance and varying compositions in different parts.
What is the experimentally useful definition of an element established by Antoine Laurent Lavoisier?
An element is a basic form of matter that cannot be broken down into simpler substances by chemical reactions.
How did Robert Boyle contribute to the classification of substances?
Robert Boyle was the first to use the term 'element' in 1661.
What are the main properties that metals typically exhibit?
Metals usually have a lustre, silvery-grey or golden-yellow color, conduct heat and electricity, and are ductile.
How can elements be classified based on their chemical composition?
Elements can be classified as metals, non-metals, and metalloids.
Who was the first scientist to establish an experimentally useful definition of an element?
Antoine Laurent Lavoisier
Explain the difference between a homogeneous mixture and a heterogeneous mixture using examples.
Homogeneous mixtures have uniform compositions, like solutions, while heterogeneous mixtures have non-uniform compositions with physically distinct parts, like mixtures of sodium chloride and iron filings.
Describe the properties of an alloy. Provide an example of an alloy and its composition.
Alloys are mixtures of two or more metals or a metal and a non-metal. They cannot be separated by physical methods, show properties of their constituents, and have variable compositions. An example is brass, which is approximately 30% zinc and 70% copper.
Differentiate between an element and a compound. Provide examples of each.
An element consists of only one type of atom and cannot be broken down further by chemical methods. A compound is composed of two or more elements chemically bonded in fixed proportions. For example, oxygen is an element, and water (H2O) is a compound.
Explain the properties typically exhibited by non-metals. Provide three examples of non-metals.
Non-metals are usually dull, brittle, poor conductors of heat and electricity, and have lower melting points compared to metals. Examples of non-metals include sulfur, carbon, and nitrogen.
What are metalloids? Give two examples of metalloids and explain their properties.
Metalloids are elements that have properties intermediate between metals and non-metals. Two examples are silicon and arsenic. They exhibit characteristics of both metals and non-metals, such as semiconducting properties.
Explain why mercury is classified as a 'pure substance'?
Mercury is classified as a pure substance because it is a single element with a uniform composition.
How can you differentiate between elements and compounds based on their composition?
Elements are substances made up of only one type of atom, while compounds are substances made up of two or more different types of atoms chemically bonded together.
Identify two metalloids and describe a characteristic property they exhibit.
Two examples of metalloids are silicon and germanium. Metalloids exhibit properties of both metals and non-metals.
List three properties that are typically exhibited by non-metals.
Non-metals are generally dull in appearance, poor conductors of heat and electricity, and brittle in solid form.
Explain why iron is considered a 'pure substance' despite being a common metal.
Iron is considered a pure substance because it is a single element with a uniform composition, consisting of only iron atoms.
What separation techniques would you apply to separate small pieces of metal in the engine oil of a car?
Filtration or magnetic separation
How would you separate butter from curd?
Churning or centrifugation
Which element is liquid at room temperature?
Mercury
List three properties typically exhibited by non-metals.
Dull appearance, poor conductors of heat and electricity, brittle
Which metalloid is commonly used in semiconductors?
Silicon
What type of change occurs when a substance undergoes a chemical reaction?
Chemical change
Identify a compound formed from two elements A and B.
Compound AB
What is the effect of increasing temperature on the solubility of a salt?
Generally increases
List three properties that metals typically exhibit.
Luster, malleability, conductivity
Which salt has the highest solubility at 293 K?
Potassium nitrate
Test your understanding of chemical and physical changes by classifying various scenarios as examples of either type. Explore the differences between chemical and physical changes, such as changes in chemical composition and properties of matter. Identify if cutting of trees, melting butter, rusting of almirah, and boiling water represent chemical or physical changes.
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