Answer:
c) Wash your hands
Explanation:
A laboratory or most popularly called as lab is a place or facility which provides controlled conditions where some educational research, scientific studies, experiments, testings, can be performed. The place is equipped with sophisticated machines, test samples, hazardous chemicals, instruments etc.
The university or college lab, there is a incharge of the lab called as the lab instructor who is responsible for all the belongings of the lab and the safety of the experimenter or the students.
After performing some experiments or testing with some chemicals, the last and the most important thing we need to do is to wash our hand with soap or hand wash. it is very important because we touch many test samples and hazardous chemical which might go inside our mouth or eyes accidentally, which might be harmful to us.
So, it is important to wash our hand at last before leaving the lab.
Answer:
B
Explanation:
A chemical change occurred, and this caused the liquid’s physical properties to change.
when we read her experiment we can see that color changed to blue, it is because new products are formed. And the temperature cause this.
Answer:
(a) 0 J
(b) -9.5 J
(c) -18 J
Explanation:
A gas expands in volume from 26.7 to 89.3 mL at constant temperature. The change in volume is:
ΔV = 89.3 mL - 26.7 mL = 62.6 mL = 0.0626 L
The work done (w) can be calculated using the following expression.
w = - P × ΔV
where,
P is the pressure
<em>(a) against a vacuum (P = 0)</em>
w = - P × ΔV = - 0 atm × 0.0626 L = 0 atm . L = 0 J
<em>(b) against a constant pressure of 1.5 atm</em>
w = - P × ΔV = - 1.5 atm × 0.0626 L × (101.3 J/1 atm.L) = -9.5 J
<em>(c) against a constant pressure of 2.8 atm</em>
w = - P × ΔV = - 2.8 atm × 0.0626 L × (101.3 J/1 atm.L) = -18 J
A model of the atom as they didnt have microscopes back then they used models to describe