SI Units (Simplified) - Online Tutor, Practice Problems & Exam Prep

SI Units (Simplified) Concept 1

We're going to say here that the international system of units, SI, is related to the metric system, and it comes with 6 base units. Now, when it comes to these 6 base units, let's take a look. We have our physical quantity, and each of these physical quantities is attached to an SI base unit. This SI base unit name has a symbol. So, when it comes to mass, the SI base name is kilogram, and its symbol is kg. Okay? So, the SI base unit for mass is kilograms. Next, we have length. Length would be meters, which is abbreviated as m. Time would be seconds, which is abbreviated as just s. Temperature. The SI unit for temperature is kelvin, which is abbreviated as K, capital K. The amount of a substance, so you need to familiarize yourself with this particular term in terms of chemistry. The amount of the substance is the mole and its symbol is mol. So, we were just to remove the e. Now, when you're doing calculations with moles later on in chemistry, you'll see them use either the full name or the symbol name. K? So just remember they're the same thing. Now for volume here, you'll see that there are 2 spots. That's because the top one is the SI base unit that we use, but you'll find time and time again that you'll not see the SI base unit used for volume, instead, you'll see the metric one. So the SI base unit for volume is going to be our cubic meters, which is m3. And here, the metric counterpart is liters. You'll see liters more often than you will see cubic meters. And the symbol for liters is just a capital L. So here we have our 6 base units, as well as 1 metric unit. In terms of volume, the metric unit of liters is oftentimes used more than the SI unit of meters cubed.

SI Units (Simplified) Example 1

Which of the following values is given with SI units? So here we have 1.25×104 minutes, 6.82×10-3 milligrams, 25.6 degrees Celsius, and 101.3 seconds. Alright. So minutes is a unit of time. We know the SI unit for time is seconds, not minutes. Next, milligrams is our units for mass, but we know kilograms is the SI unit for mass. Celsius, units for temperature, but we know temperature should be in Kelvin when we're dealing with SI units. Here, out of all our options, option d is the correct choice. Seconds is an SI base unit.

Which of the following represents volume in SI units? 

• A. 2.71×10^–1 cm³
• B. 207.2 km²
• C. 5.81×10⁵ m³
• D. 582.28 mm

Convert 12 minutes into acceptable SI units.

• A. 720 s
• B. 0.20 s
• C. 3.33×10^–3 s
• D. 4.32×10⁴ s