Dissolving an ionic compound is a chemical change. In contrast, dissolving sugar or another covalent compound is a physical change because chemical bonds are not broken and new products are not formed .Dissolving a solid in liquid, such as table salt in water, is a physical change because only the state of the matter has changed. Physical changes can often be reversed. ... It has not combined with the water to cause a chemical reaction
(a) chlorine gains an electron from a sodium atom
Answer:
1.7L
Explanation:
Given parameters:
Volume of hydrogen gas = 1.7L
Unknown:
Volume of water produced = ?
Solution:
A synthesis reaction is a combination reaction that involves two or more substances combining together to give a product.
In the synthesis of water, hydrogen gas and oxygen gas are reacted to give water as a product according to the expression below;
2H₂ + O₂ → 2H₂O
Assuming that the reaction takes place at STP, it is easier to solve this problem.
Now, oxygen gas must be the excess reactant because it is freely available.
Find the number of moles of the known specie first,
Number of moles = 
Number of moles of H₂ = 
= 0.076moles
From the balanced reaction equation;
2 moles of H₂ produced 2 moles of H₂O
0.076 moles of H₂ will produce 0.076 moles of H₂O;
Volume of water produced = number of moles x 22.4
= 0.076 x 22.4
= 1.7L
Answer:
- <u>Option </u><u><em>B) As the car is moving quickly toward you.</em></u>
Explanation:
The higher the frequency of the sound wave the higher the pitch. So, the sound with the highest frequency will have the highest pitch.
When the source of a sound (the car) has a relative motion to an observer (you) there is an apparent change in the frequency of the sound wave. This is known as the Doppler effect.
As the source of the sound is moving toward the observer, the sound waves will shorthen their wave length, so, since the inverse relation between the wave length and the frequency, the result is an apparent increase of the frequency of the sound.
The faster the source is moving toward you (the observer) the greater the effect (increase of the frequency) and so the higher the pitch. This is what the option B) describes: as the car is moving quickly toward you, you would hear the highest pitch.
The opposite happens when the source of the sound moves away from the observer: the pitch lowers.
The Doppler effect is also observed with the light waves: when the light source is moving toward the observer the apparent change in the frequency implies a blue shift, when the source is moving away of the observer the apparent increase of the frequency leads to a red shift.
