<h3>
Answer:</h3>
28.17 %
<h3>
Explanation:</h3>
In the question we are required to determine the percent by mass of nitrogen in (NH₄)₃PO₄.
- To calculate the percent by mass of an element in a compound we use the formula;
- % by mass =(Mass of the element÷ Relative formula mass of the compound)100
In this case;
- Atomic mass of nitrogen is 14.0 g/mol
But; There are three nitrogen atoms in (NH₄)₃PO₄.
Therefore; Mass of nitrogen in (NH₄)₃PO₄ = 14.0 × 3
= 42 g
The relative formula mass of (NH₄)₃PO₄ = 149.0867 g/mol
Thus;
% by mass of N = (42 g ÷ 149.0867 g/mo)× 100%
= 28.17 %
Therefore, the % by mass of N is (NH₄)₃PO₄ is 28.17%
Answer: B (Items with densities lower than water will sink due to surface tension)
Explanation:
Surface tension is an intermolecular force exerted on the surface of water making it like a stretch elastic skin. Surface tension enables items with lesser densities than water, to float and slide on a water surface. Examples insects, leaves, paper etc
According to Archimedes principle an object denser than the fluid will sink. While objects less dense than the fluid will float.
Answer is (B) is false because items with densities higher then water will sink due to surface tension
Answer:
A. A scientist investigates a mouse's growth in nature by watching the animal.
A field study is a raw collection of data, typically in the natural habit of the organism; hence why an experiment taken in a lab isn't a field study.
