Grade 6 Science Notes and Review Questions (DepEd-Based): First Quarter
Quick notes in outline form and practice questions to help learners review the topics covered in Grade 6 Science (First Quarter) based on the DepEd curriculum.
This page contains quick notes and review questions for the following topics in Grade 6 Science – First Quarter:
- Module 1
- Describing Mixtures
- Differentiating a Solute from a Solvent
- Factors Affecting Solubility
- Solutions and Their Characteristics
- Colloids and Their Characteristics
- Suspensions and Their Characteristics
- Module 2
- Separating Mixtures Through Filtering and Sieving
- Separating Mixtures Through Evaporation
- Separating Mixtures Through Decantation
- Separating Mixtures Using Magnets
You can download printable (PDF) copies of the notes and the practice exam below.
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Science 6: Quick Notes
Quarter 1 Module 1
Describing Mixtures
Mixtures
- combinations of two or more substances
- can be homogeneous or heterogeneous
Homogeneous mixtures
- appear uniform all throughout because they have the same proportion
Heterogeneous mixtures
- combined substances are not evenly spread or mixed
- not uniform in proportion of solute to solvent
- the components of the mixture can still be recognized
Differentiating a Solute from a Solvent
Solution
- a mixture that is formed when one substance dissolves into another
- homogeneous
- consists of a solute and a solvent
Solute
- the substance that is being dissolved
- usually the one that is smaller in amount
- a solution can have one or more solutes
Solvent
- the substance that does the dissolving
- usually the one that is larger in amount
- water is the “universal solvent”
Soluble vs. insoluble
- Not all solutes can be dissolved in all solvents. If a certain solute can be dissolved in a certain solvent, it is described as soluble [in that solvent]; if a solute cannot be dissolved, it is described as insoluble [in that solvent].
Factors Affecting Solubility
Solubility
- the maximum amount of a solute that will dissolve in a given amount of solvent at a specific temperature
- affected by several factors:
- nature of solute and solvent
- temperature of solvent
- manner of stirring
- amount of solvent
- size of the solute
Concentration
- how much solute is dissolved in a given amount of solvent
Dilute vs. concentrated
- dilute – a solution that has a small amount of solute
- concentrated – a solution that has a lot of solute
Solutions and Their Characteristics
Characteristics of a solution:
- It is a homogeneous or uniform mixture.
- It may be formed by any two substances that can be evenly mixed.
- It exists in any phase.
- Note: Even if it is made of different phases, if the result exists in a single phase, it is a solution.
- Example of a solid solution: steel (iron, carbon, etc.)
- Example of a gaseous solution: air (nitrogen, oxygen, etc.)
- It does not scatter beams of light.
- It is stable over time.
- The solute and the solvent cannot be distinguished by the naked eye.
- The solute cannot be separated from the solvent by mechanical means (such as filtration).
Colloids and Their Characteristics
Colloid
- a type of mixture in which particles are dispersed uniformly throughout a gas, liquid or solid
- examples: blood, whipped cream, fog
Components:
- Dispersed phase
- refers to the substance being dispersed
- usually present in a relatively small amount
- Dispersion medium
- the substance or solution throughout which particles are dispersed
- usually the more abundant substance in a colloid
- also called the continuous phase
To be classified as a colloid, the substance in the dispersed phase must be:
- larger than the size of a molecule, BUT
- smaller than can be seen with the naked eye.
Tyndall effect
- the effect of light scattering in a colloidal dispersion
- used to determine whether a mixture is a true solution or a colloid
- if no light is shown/scattered, it is a true solution
- if the light can be readily seen, it is a colloid, because it is the particles that scatter the light in all directions, making it easy to see
Types of colloids: (mnemonic: SAFE)
- sol – solid particles in a liquid
- aerosol – liquid/solid particles dispersed in a gas – ex. fog, mist, smoke
- foam – gas particles in a liquid – ex. soap suds, whipped cream
- emulsion – two liquids – ex. oil in water, milk
Suspensions and Their Characteristics
Suspension
- a kind of heterogeneous mixture where particles that are visible to the naked eye settle at the bottom when left undisturbed
- appears cloudy when mixed
- examples: soil and water, sand in the sea
Quarter 1 Module 2
Separating Mixtures Through Filtering and Sieving
Filtering
- separates solid and liquid components using filter paper or cloth
- the liquid passes through, leaving the solid behind
Sieving
- separates two solid materials of different sizes using a sieve
- the smaller passes through, leaving the bigger behind
Separating Mixtures Through Evaporation
Evaporation
- process of separating mixtures which involves heating the solution until the solvent evaporates, leaving behind a solid residue
- example: salt solution
Separating Mixtures Through Decantation
Decantation
- technique used in separating substances of different densities
- the mixture must be left undisturbed (so that the less dense substance is at the top)
- the less dense substance can be removed by scooping or pouring it out
- example: oil in water, gasoline in water, fats floating in soup
Separating Mixtures Using Magnets
Magnets
- can be used to separate metallic from non-metallic objects
- metals most attracted to magnets: iron (and its alloys, incl. steel), nickel, cobalt
- no chemical reaction involved
- example: metals and nonmetals, iron filings from sawdust
Practice Exam: Review Questions for First Quarter
1. A mixture is a combination of two or more substances. When it appears uniform all throughout, it is called a _____.
a. homogeneous mixture
b. heterogeneous mixture
c. homozygous mixture
d. heterozygous mixture
2. Which of the following does NOT describe a heterogeneous mixture?
a. The composition of the mixture is the same all throughout.
b. The composition of the mixture is visible.
c. The composition of the mixture can be easily identified.
d. None – all are correct
3. A mixture that is formed when one substance dissolves into another is called a _____.
a. solute
b. solvent
c. solution
d. compound
4. Which of the following statements is correct?
a. A solution is a heterogeneous mixture.
b. A solvent is the substance that is being dissolved.
c. A solute is the substance that does the dissolving.
d. Water is called the “universal solvent” because it is able to dissolve more substances than any other liquid.
5. Which of these factors affect solubility?
a. the size of the solute
b. the amount of the solvent
c. the temperature of the solvent
d. all of the above
6. True or false – A solution always consists of a liquid solvent and a solid solute.
a. True
b. False
7. Steel is an example of a _____.
a. colloid
b. compound
c. solution
d. suspension
8. Clean air is an example of a _____.
a. colloid
b. compound
c. solution
d. suspension
9. Which of these mixtures is homogeneous?
a. colloid
b. solution
c. suspension
d. all of the above
10. Which of these mixtures is heterogeneous?
a. colloid
b. solution
c. suspension
d. a and c
11. Three beakers contain a solution, a colloid, and a suspension, but you don’t know which is which. You notice that in one of the beakers, particles have settled at the bottom. This must be the _____.
a. colloid
b. solution
c. suspension
12. Three beakers contain a solution, a colloid, and a suspension, but you don’t know which is which. In one of the beakers, particles have NOT settled at the bottom over time, and when you shine a light through it, the light scatters, like car headlights in a fog. This must be the _____.
a. colloid
b. solution
c. suspension
13. The _____ is used to determine whether a mixture is a true solution or a colloid.
a. Tydings-McDuffie law
b. Tyndall effect
c. Tycho Brahe test
d. Tympanic membrane
14. Aerosol, foam, emulsion, and sol are types of _____.
a. colloids
b. solutions
c. suspensions
d. all of the above
15. This is a type of mixture where liquid or solid particles are dispersed in a gas. Examples include fog, mist, and smoke.
a. emulsion
b. aerosol
c. gel
d. foam
16. When you go to the beach, you notice that rough waves or swimmers can disturb the sand in the sea but it usually settles back down to the bottom. This is an example of a _____.
a. colloid
b. compound
c. solution
d. suspension
17. At construction sites, stones and all sorts of debris can get mixed into the sand. To get the stones out, construction workers often use which separation technique?
a. sieving
b. evaporation
c. decantation
d. distillation
18. You can use a magnet to separate _____.
a. sand from gravel
b. sand from aluminum powder
c. sand from iron filings
d. sand from sugar
19. You need to separate two liquids that have different densities. Which separation technique can you use?
a. filtration
b. decantation
c. using a magnet
d. sieving
20. When you dry your clothes by spinning them in the washing machine, you are using a separation technique called centrifugation. But when you dry the clothes by hanging them outside, on a clothesline, under the heat of the sun, you are using which separation technique?
a. still centrifugation
b. filtration
c. evaporation
d. distillation