Number of significant figures will be 1.
Given:
weight of acetylsalicylic acid = 0. 4g
Significant figures are the digits of value which carry meaning towards the resolution of the measurement. They are also called significant figures in chemistry. All the experimental measurements have some kind of uncertainty associated with them.
When we convert 0.4g acetylsalicylic acid to mg we get value 400mg
when we convert 400mg to gram we get value of 0.4 gram
Since 0 before a decimal is not significant so there is only one significant figure that is 4.
<h3>How do you determine the number of significant figures?</h3>
- The zero to the left of a decimal value less than one is meaningless.
- All trailing zeros that are placeholders are meaningless.
- The presence of zeros between non-zero numbers is significant.
- Non-zero numbers are all significant.
- If a number contains more digits than the desired number of significant digits, it is rounded.
<h3>Why 'Hidden Figures' is so important?</h3>
It's an important story for a variety of reasons, and it comes at a time when people are looking to Hollywood more than ever to tell stories that represent them. Hidden Figures is that movie for many, and it's critical that everyone sees these women in action. This is why. This film tells a story that you've probably never heard before.
Learn more about Significant figure here:
<u><em>brainly.com/question/24491627</em></u>
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<span>136.14 g/mol </span><span><span>Calcium sulfate, Molar mass</span></span>
Answer :
The atomic mass is the sum of the number of protons and neutrons in the nucleus of an atom.
Explanation :
Atomic number : it is defined as the number of protons or number of electrons.
Atomic number = number of protons = number of electrons
Mass number or atomic mass : It is defined as the sum of the number of protons and the number of neutrons.
Mass number or atomic mass = Number of protons + Number of neutrons
For example :
Number of protons in carbon = 6
Number of neutrons in carbon = 6
Mass number or atomic mass = Number of protons + Number of neutrons
Mass number or atomic mass = 6 + 6
Mass number or atomic mass = 12
Thus, the atomic mass is the sum of the number of protons and neutrons in the nucleus of an atom.
That will make a gold-202 nucleus.
<h3>Explanation</h3>
Refer to a periodic table. The atomic number of mercury Hg is 80.
Step One: Bombard the 
with a neutron 
. The neutron will add 1 to the mass number 202 of 
. However, the atomic number will stay the same.
- New mass number: 202 + 1 = 203.
- Atomic number is still 80.
.
Double check the equation:
- Sum of mass number on the left-hand side = 202 + 1 = 203 = Sum of mass number on the right-hand side.
- Sum of atomic number on the left-hand side = 80 = Sum of atomic number on the right-hand side.
Step Two: The 
nucleus loses a proton 
. Both the mass number 203 and the atomic number will decrease by 1.
- New mass number: 203 - 1 = 202.
- New atomic number: 80 - 1 = 79.
Refer to a periodic table. What's the element with atomic number 79? Gold Au.
.
Double check the equation:
- Sum of mass number on the left-hand side = 203 = 202 + 1 = Sum of mass number on the right-hand side.
- Sum of atomic number on the left-hand side = 80 = 79 + 1 = Sum of atomic number on the right-hand side.
A gold-202 nucleus is formed.
