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Answer:</h3>
Seconds (s)
Liters (L)
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Explanation:</h3>
SI units relate to the International System of Units. These units are the base, metric units that are most commonly accepted for different measurements.
Common SI Units
The most common SI units are as follows:
- Length - meter (m)
- Time - second (s)
- Mass - kilogram (kg)
- Amount of substance - mole (mole)
- Electric current - ampere (A)
- Temperature - kelvin (K)
- Volume - liter (L)
*Note that gram (g) is not an SI unit
Each type of measurement will only have 1 SI unit. This is the unit that will be expected for most answers. Sometimes this means converting an answer into a different unit so it is more widely accepted.
Why SI Units are Important
SI units are important for the same reason that the metric system is used. It gives a standardized list of measurements that scientists across the world can use. Also, it makes it easier to compare scientific findings and studies when all of the measurements are given in the same units.
There are times when it is unrealistic to use SI units. For example, when discussing space, using meters will not be realistic due to the size of space. Also, when measuring the mass of small elements, kilograms are too large. But otherwise, SI units should be used.
Explanation:
The electronegativity difference in C-C and C-H atoms is quite low. This means smaller the electron cloud. This further means larger bond length that is electron's are further from the nucleus. hence, higher potential energy of C-C and C-H bonds.
On the contrary, C-O and H-O have large difference in electronegativity( O is high electronegative element) . This means smaller bond length. Electron's near the nucleus. Thus, lower potential energy of bonds.
<h3><u>Answer;</u></h3>
C) A convex lens has a thick center and thin edges; a concave lens has a thin center and thicker edges.
<h3><u>Explanation;</u></h3>
- Convex lens refers to the lens which merges the light rays at a particular point, that travels through it, while a concave lens can be identified as the lens which disperses the light rays around, that hits the lenses.
- A convex lens is thicker at the center, as compared to its edges, while a concave lens is thinner at the center as compared to its edges.
- A concave lens is thicker at the edges than in the middle and spreads light rays apart producing an image smaller than the actual object. A convex lens on the other hand, is thinner at the edges and thicker towards the center, that is they are bent towards a central point.
Answer:
Example
0.5 mol of sodium hydroxide is dissolved in 2 dm3 of water. Calculate the concentration of the sodium hydroxide solution formed.
Concentration =
Concentration = 0.25 mol/dm3
Volume units
Volumes used in concentration calculations must be in dm3, not in cm3. It is useful to know that 1 dm3 = 1000 cm3. This means:
divide by 1000 to convert from cm3 to dm3
multiply by 1000 to convert from dm3 to cm3
For example, 250 cm3 is 0.25 dm3 (250 ÷ 1000). It is often easiest to convert from cm3 to dm3 before continuing with a concentration calculation.
Question
100 cm3 of dilute hydrochloric acid contains 0.02 mol of dissolved hydrogen chloride. Calculate the concentration of the acid in mol/dm3.
Reveal answer
Converting between units
The relative formula mass of the solute is used to convert between mol/dm3 and g/dm3:
to convert from mol/dm3 to g/dm3, multiply by the relative formula mass
to convert from g/dm3 to mol/dm3, divide by the relative formula mass
Remember: the molar mass is the Ar or Mr in grams per mol.
Example
Calculate the concentration of 0.1 mol/dm3 sodium hydroxide solution in g/dm3. (Mr of NaOH = 40)
Concentration = 0.1 × 40
= 4 g/dm3
A. the wax is a both; 1. physical change-solid to liquid.
2. chemical change- burned to CO2 + H20 + heat + carbon as seen as black on the rod
b. the wick is neither; the wick does not change, just provides conduit for wax to flame
c. the glass rod is physical change; the carbon is only deported
HOPE THIS HELPS, IVE ALSO LEARNING BEEN LEARNING THIS RECENTLY