Selenium (Se) the most common isotope of this element. The nucleus consists of 34 protons (red) and 46 neutrons (blue).
8 because atomic number is the same as number of protons, protons and electrons have the same amount so that the element is neither positive nor negative.
The sedimentary rock formed when water deposits tiny particles of clay in very thin flat layers is called limestone.
Answer:
Approximately 
, assuming that this gas is an ideal gas.
Explanation:
Look up the standard room temperature and pressure:
and 
.
The question states that the volume of this gas is 
.
Convert the unit of all three measures to standard units:
.
.
.
Look up the ideal gas constant in the corresponding units: 
.
Let 
denote the number of moles of this gas in that . By the ideal gas law, if this gas is an ideal gas, then the following equation would hold:
.
Rearrange this equation and solve for :
.
In other words, there is approximately 
of this gas in that .
Answer:
7.3 × 10¹ m²
Explanation:
The language "product" means that we must multiply the numbers given to get our answer.
9.0 × 10⁻⁴ m × 8.1 × 10⁴ m = 7.3 × 10¹ m²
The significant figures rule for multiplication is that we must us the amount of significant figures in the number with the least significant figures, in this question this is 2 significant digits from both 9.0 × 10⁻⁴ m and 8.1 × 10⁴ m.
