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
<span> Greenhouse gases were not historically present in the atmosphere.</span>
An exothermic reaction is a type of chemical reaction in which energy is released to the environment in form of heat or light. Endothermic reaction in the other hand is a chemical reaction where energy is taken from the surroundings and thus the surroundings end up with less energy than they started with. In this case; the above reaction is an Exothermic reaction (heat is being released to the surroundings).
Answer:
A. How much decay happens in each flashlight
Explanation:
In an experiment, the DEPENDENT OR RESPONDING VARIABLE is the variable that responds to changes being made to another variable called Independent variable. It is the variable that is measured by an experimenter.
In this question, an experiment was carried out to research the effect of sunlight on plastic decay. Three plastic flashlights were used for this experiment in which one was placed in a dark closet (control), and the others were placed in light at different times or intervals. However, the variable being measured or assessed is the decay of each flashlight. This means that "HOW MUCH DECAY HAPPENS IN EACH FLASHLIGHT" is the dependent variable.
Answer:
Magnesium
Explanation:
Magnesium is above iron in the reactivity series, which means that Mg can take oxygen from iron as it is a more reactive metal.
