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4 years ago

Explain the differences between a physical and chemical change, and give examples of each.

1 answer:

4 0

Chemical change: a reaction/event where the chemicals/elements present before the change are NOT the same molecules present after the change.
For example, combustion reactions such as the burning of wood or rubbing alcohol are examples of chemical change. The reactants before the combustion of rubbing alcohol are CH3O (rubbing alcohol) and O2 oxygen (oxygen). The molecules present after the combustion reaction are CO2 (carbon dioxide) and H2O (water vapor).

Physical Change: a change in structure or state of a substance but, after the change the material is the same material that we started with. One example would be breaking a glass bottle by dropping it. The glass is now in smaller pieces than when we started, but the glass molecules are still glass molecules.

Hope this helped! Leave any questions you still have for me in the comments below!

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Given that the distance from the left end of the string to the first antinode is 27.5 cm , calculate the wavelength of the stand

ivolga24 [154]

Answer:

= 0.55 m

Explanation:

A standing wave is characterized by anti-nodes and nodes.

Antinodes are points on a standing wave at maximum amplitude, while nodes are points on the standing wave that are stationary and have zero amplitude.

The distance between two adjacent nodes or two adjacent anti-nodes is equivalent to half the wavelength.

Therefore, in this case the half wavelength is 27.5 cm.

Thus, wavelength = 27.5 × 2

= 55 cm

= 0.55 m

6 0

3 years ago

What is the kinetic energy of a 0.135 kg baseball thrown at 40 m/s

Ronch [10]

KE = 1/2 * m * v^2
KE = 1/2 * 0.135 * 40^2
KE = 1/2 * 0.135 * 1600
KE = 108 J

4 0

3 years ago

What mRNA sequence would result from the following DNA sequence?

Nezavi [6.7K]

Answer:

UAC CUG AGG AUC

Explanation:

The mRNA sequence from ATG GAC TCC TAG DNA sequence would be UAC CUG AGG AUC.

According to Chargaff's base pairing rule, the purine bases always pair with pyrimidine bases. Specifically, Adenine base must pair with Thymine base while Guanine base must pair with Cytosine base. In RNA, Thymine base is replaced with Uracil base.

Hence:

ATG GAC TCC TAG will pair with

UAC CUG AGG AUC

5 0

3 years ago

Inez uses hairspray on her hair each morning before going to school. The spray spreads out before reaching her hair partly becau

Tamiku [17]

Answer:

$7.0\cdot 10^{-13}C$

Explanation:

The magnitude of the electrostatic force between two charged objects is

$F=k\frac{q_1 q_2}{r^2}$

where

k is the Coulomb's constant

q1 and q2 are the two charges

r is the separation between the two charges

The force is attractive if the charges have opposite sign and repulsive if the charges have same sign.

In this problem, we have:

$r=0.070 cm =7\cdot 10^{-4} m$ is the distance between the charges

$q_1=q_2=q$ since the charges are identical

$F=9.0\cdot 10^{-9}N$ is the force between the charges

Re-arranging the equation and solving for q, we find the charge on each drop:

$F=\frac{kq^2}{r^2}\\q=\sqrt{\frac{Fr^2}{k}}=\sqrt{\frac{(9.0\cdot 10^{-9})(7\cdot 10^{-4})^2}{8.99\cdot 10^9}}=7.0\cdot 10^{-13}C$

8 0

3 years ago

In which type of collision is no kinetic energy converted to heat or sound energy?

mezya [45]

Answer:

elastic collision

An elastic collision occurs when the two objects "bounce" apart when they collide. Two rubber balls are a good example. In an elastic collision, both momentum and kinetic energy are conserved. Almost no energy is lost to sound, heat, or deformation.

I hope it's helpful!

5 0

3 years ago