Answer:
H+ and NO3- ions
Explanation:
The Pb²+ ions react with the SO4²‐ ions to form a solid precipitate, i.e. they bond together and undergo a phase change;
On the contrary, the H+ and NO3- ions are aqueous ions before the reaction and the same after the reaction, i.e. they don't change;
Hence, the H+ and NO3- ions are spectator ions
The way to do this type of question is to consider what changes and what doesn't, look at phase changes and oxidation state changes
Explanation:
Since pressure remained constant, we can eliminate P from the equation

Doing some algebra and converting temperature to Kevin by adding 273, you should obtain the same result.
Answer: The correct answer is (D).
Explanation:
Space photography help astronomers:
- To visualize and observe the position and appearance of celestial objects like: path of orbiting planets ,dim stars which invisible to naked eyes ,far away galaxies etc.
- To observe any phenomena which is occurring at macro level for example: collision of steroids and meteors etc.
Answer:
synthesis reaction
Explanation:
A synthesis reaction occurs when two or more reactants combine to form a single product. In a decomposition reaction, one reactant breaks down into two or more products. This is the reverse of a synthesis reaction. Replacement reactions occur when elements switch places in compounds.