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3 years ago

Help pls!! What is the difference between physical change and chemical change?

Chemistry

2 answers:

juin [17]3 years ago

8 0

Answer:

The difference between a physical reaction and a chemical reaction is composition. In a chemical reaction, there is a change in the composition of the substances in question. In a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition

Hope this helped! :) Have a wonderful day/night!

MaRussiya [10]3 years ago

4 0

Physical change does not make a new chemical/object. A chemical change does.

Chemical Change example: Combining liquid and liquid to create a new substance

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noah rides his bike with a constant speed of 8 km/h. How long will he take to travel a distance of 16 kilometers?

katovenus [111]

Answer:

d/t=s

(divide 16)16/t= 8(divide 16)

t= 0.5 km/h²

Explanation:

Distance: 16 kilometres

Speed: 8 km/h

Time: ?

3 0

3 years ago

Read 2 more answers

Each molecule of lycopene contains 40 atoms of carbon (plus other atoms). The mass percent of carbon in lycopene is 84.49%. What

IrinaK [193]

Answer: 568g/mol

Explanation:

It should be noted that there are 40 atoms of carbon in lycopene.

Since mass of 1 carbon = 12g/mol

Mass of 40 carbon atoms = 40 × 12g/mol = 480g/mol

Let the molar mass of lycopene be represented by x.

Therefore the molar mass of carbon = x × mass percent of carbon in lycopene

x × 84.49% = 480g/mol

x × 0.8449 = 480g/mol

x = 480/0.8449

x = 568g/mol

The molar mass of lycopene is 568g/mol

5 0

3 years ago

50.0 mL of 0.200 M HNO2 is titrated to its equivalence point with 1.00 M NaOH. What is the pH at the equivalence point?

yKpoI14uk [10]

Answer:

8.279

Explanation:

The pH can be determined by hydrolysis of a conjugate base of weak acid at the equivalence point.

At the equivalence point, we have

$n_{NaOH}=n_{HNO_2}$

= 25.00 x 0.200

= 5.00 m-mol

= 0.005 mol

Volume of the base that is added to reach the equivalence point is

$\frac{0.005}{1.00} \times 1000= 5.00 \ mL$

Number of moles of $NO^-_{2}=n_{HNO_2}$

= 0.005 mol

Volume at the equivalence point is 25 + 5 = 30.00 mL

Therefore, concentration of $NO^-_{2}= \frac{5}{30}$

= 0.167 M

Now the ICE table :

$NO^-_2 + H_2O \rightarrow HNO_3 + OH^-$

I (M) 0.167 0 0

C (M) -x +x +x

E (M) 0.167-x x x

Now, the value of the base dissociation constant is ,

$K_w=K_a \times K_b$ $(K_w \text{ is the ionic product of water })$

$K_b =\frac{K_w}{K_a}$

$K_b =\frac{1 \times 10^{-14}}{4.6 \times 10^{-4}}$

= $2.174 \times 10^{-11}$

Base ionization constant, $K_b = \frac{\left[HNO_2\right] \left[OH^- \right]}{\left[NO^-_2 \right]}$

$2.174 \times 10^{-11}=\frac{x^2}{0.167 -x}$

$x= 1.9054 \times 10^{-6}$

So, $[OH^-]=1.9054 \times 10^{-6 } \ M$

pOH =- $\log[OH^-]$

= $- \log(1.9054 \times 10^{-6} \ M)$

=5.72

Now, since pH + pOH = 14

pH = 14.00 - 5.72

= 8.279

Therefore the ph is 8.279 at the end of the titration.

8 0

3 years ago

All the following are steps included in linking amino acids to form chains except

ss7ja [257]

The correct option is D.
During peptide formation, when two amino acids come together, a hydrogen atom and two molecules of oxygen are released in form of water molecules. The amino acid that present the carboxyl group to the reaction loses an hydroxyl group while the amino acid that present the amino group to the reaction loses a hydrogen.

4 0

3 years ago

Most thermal conductors are made of which material?

In-s [12.5K]

Answer:

copper

Explanation:

5 0

3 years ago