a substance dissolves.
like adding a soluble salt to water, it just dissolves, i.e dissociates homogeneously as water is able to dissociate salts (ionic compounds) into its ions. (it can also dissociate other non-ionic compounds like HCL)
the salt still remains chemically as a salt and is unchanged chemically thus it is not an indication of a chemical reaction as no chemical reaction has taken place.
the formation of a precipitate is a chemical reaction because a new substance (i.e new chemical) is formed. For example adding aqueous sodium hydroxide into an aqueous solution with CU2+ cations will form a blue precipitate (that is copper (II) hydroxide which is insoluble, hence it precipitates). Since a new chemical is formed, a chemical reaction has taken place and thus indicates a chemical reaction.
color change... im not sure but usually a color change will only occur when a new substance is formed. Like iron corrodes (i.e rust) slowly in moist air to form hydrated iron (III) oxide that is rust. (brown color).
usually adding a mixture to a mixture has little energy change, i.e little heat taken in by the reaction mixture or little heat given out by the reaction mixture. Whereas when a new substance is formed, there is usually noticeable energy change like the container gets colder or hotter (without heat being supplied of course). For example dissolving basic oxides into water releases energy ( more energy released than gained = exothermic reaction).
i think that should be the answer... hope it helped :D
Answer:
Question #1- Scientists agree to a standard way of reporting measured quantities in which the number of reported digits reflects the precision in the measurement- more digits, more precision; less digits, less precision. You just studied 14 terms!
Question #2- Units are important because without proper measurement and units to express them, we can never express physical laws precisely just from qualitative reasoning. Units are incredibly important to physics. Two of the most important reasons are the following: (1) they help us. to avoid making mistakes in computation, and (2) they serve as a check on computations once they are completed. In the first case, you can avoid adding 3m and 25cm and coming up with the wrong answer.
Explanation: Hope this helps please mark brainliest!
Answer:
PLEASE MARK AS BRAINLIEST!!
Explanation:
ANSWER IS IN THE IMG BELOW
Answer:
c. natural force or pull toward the earth
Explanation:
Gravity of the earth is the force of attraction that it naturally possesses to attract any mass.
An apple falls on the earth due to this force of gravity.
The force of gravity near to the surface of the earth is given as:
where:
m= mass of the body
g= acceleration due to gravity
The variation of the gravitational force with height is given as:
where:
where
R = radius of the earth 
V = 340 m/s
f = 256 Hz
lambda (wavelength)
v = f*lambda
340 = 256 * lambda
340/256 = lambda
lambda = 1.328 m
