The device is an anemometer<span>
It's like 4 cups that measure the speed instead of direction
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Density of powder 1 = 0.5 g / 45 cm^3 = 1/90 g/cm^3
Density of powder 2 = 1.3 g / 65 cm^3 = 1/50 g/cm^3
Therefore the densities of the two powders are different, hence chemical reaction has occurred.
(note: none of the other choices make sense. In fact, a different density does not necessarily indicate a chemical change, see paragraph below).
Density of powders are not definitive unless they are each of the same size and texture. For example, granular sugar, rock sugar, and icing sugar all have different densities. I would conclude that this experiment does not lend to a reliable answer.
Answer:
Heat of reaction or enthalpy of reaction (ΔH)
Explanation:
The heat of reaction or enthalpy of reaction (ΔH) is the amount of heat energy that the system must release or absorb so that the temperature remains constant throughout the chemical reaction process. In other words, the heat of reaction or enthalpy of reaction (ΔH) is the change in the enthalpy of a chemical reaction (the energy absorbed or released into it) that occurs at a constant pressure.
Then, this energy can be observed in the following way:
Every substance has a quantity of energy stored in its links. When the energy contained in the reagents is greater than that contained in the products, the reaction is exothermic because energy release occurs. When the energy contained in the reagents is less than that contained in the products, an endothermic reaction occurs because energy absorption occurs.
That energy contained in the substances is called enthalpy (H).
Then the enthalpy can be defined as the difference between the sum of the enthalpies of the products and the sum of the enthalpies of the reactants.
Answer:
c. 3/2 mg
Explanation:
Given that the acceleration of an elevator is 1/2 g upward.
The reading on the scale of the elevator is the net external force acting on the elevator.
Let the force F acting on the elevator as shown,
By using Newton's 2nd law, 
where, 
is the net force acting on the elevator.
m is the mass of the elevator,
a is the acceleration of the elevator, as given a=1/2 g upward.
So, 
So, the reading on the scale in the elevator is 
.
Hence, option (c) is correct.
The pitch of the sound is perceived to be lower when an object is approaching you while making a sound.
<h3>What is sound?</h3>
Sound is a type of vibration capable of propagating in a suitable media (e.g., air or water).
The sound waves are called acoustic waves and they have a well-defined frequency and amplitude.
In conclusion, the pitch of the sound is perceived to be lower when an object is approaching you while making a sound.
Learn more about sound waves here:
brainly.com/question/1199084
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