Question 1 (2 points)
Which option can be classified as a pure substance?

Question 1 options:

heterogenous mixture


solution


homogenous mixture


compound

Question 2 (2 points)
Law of conservation of mass states that:

Question 2 options:

matter is destroyed


matter does not change


matter is neither created nor destroyed


matter is created

Question 3 (2 points)
What is a property of bases?

Question 3 options:

all of the above


Sour taste


Slippery touch


Ability to form hydronium ions+

Question 4 (2 points)
Which property do solutions with low pH values have?


What does it mean to have a neutral pH? - Aseptic Health

Question 4 options:

have a -OH group


feels slippery


turns litmus paper blue


tastes sour

Question 5 (2 points)
How do the products of chemical reactions compare to their reactants?

Question 5 options:

The products often have completely different properties than the reactants.


The products are usually more toxic than the reactants.


The products usuallyhave more mass than the reactants.


The products usually have more atoms than the reactants.

Question 6 (2 points)
Which of the following is an example of a physical change?

Question 6 options:

Water freezing into ice.


A piece of wood burning.


A toy car rusting.


Zinc producing hydrogen gas when mixed with water.

Question 7 (2 points)
What might happen if you mixed a strong acid with an equally strong base?

Question 7 options:

You would see an explosive chemical reaction.


The base would destroy the acid.


You'd wind up with a pH-neutral salt and water.


The acid would destroy the base.

Question 8 (2 points)
In the equation shown, what are the reactants?

2H2+O2àH2O

Question 8 options:

Hydrogen and oxygen molecules (2H2 and O2 )


Ice crystals


Hydrogen atoms (H)


Water molecules (H2O)

Question 9 (2 points)
Which phrase most accurately describes a chemical change?

Question 9 options:

A change in form


A change in taste


A change on the molecular level


A change in appearance

Question 10 (2 points)
What does it mean when there is a physical change?

Question 10 options:

A new substance has been formed.


Matter has changed from one substance into a new substance.


Matter has changed size, shape or form


Matter has changed on the molecular level.

help pls ill give 20 points!

Answer:  E

1

−

E

4

=

Δ

E

=

−

2.18

×

10

−

18

J

(

1

n

2

f

−

1

n

2

i

)

=

−

2.18

×

10

−

18

J

(

1

1

2

−

1

4

2

)

=

−

2.18

×

10

−

18

J

(

15

16

)

=

−

2.04

×

10

−

18

J

After you obtain the energy, then you can realize that that energy has to correspond exactly to the energy of the photon that came in:

|

Δ

E

|

=

E

photon

=

h

ν

=

h

c

λ

where  

h

is Planck's constant,  

c

is the speed of light, and  

λ

is the wavelength of the incoming photon. Thus, the wavelength is:

⇒

λ

=

h

c

E

photon

=

(

6.626

×

10

−

34

J

⋅

s

)

(

2.998

×

10

8

m/s

)

2.04

×

10

−

18

J

=

9.720

×

10

−

8

m

=

97.20 nm

Explanation:

Explanation:

what properties are you talking about?

Answer:

At this point the volume of the gas is halved. If the pressure on the piston is again doubled, the volume of gas decreases to one-fourth its original volume. FIGURE 9.8 Boyle's Law: At constant temperature, the volume of a gas sample is inversely proportional to the pressure.

The volume of the gas doubles.

Boyles law state that the pressure of a gas is indirectly proportional to the volume at constant temperature. It is given by:

PV = constant

Let us assume that initially the pressure is P and the volume is V, hence:

[tex]P_1=P,V_1=V[/tex]

The volume decreases to half its original value, hence:

[tex]P_2=\frac{P}{2}[/tex]

Therefore:

[tex]P_1V_1=P_2V_2\\\\\\PV=\frac{P}{2}V_2\\\\V_2=2V[/tex]

Therefore the volume of the gas doubles.

Find out more at: https://brainly.com/question/1437490

Answer:

The electron configuration of the neon atom. American chemist Gilbert Lewis (1875-1946) used this observation to explain the types of ions and molecules that are formed by other elements. He called his explanation the octet rule.

The carbon atoms are sp3 hybridized.

Hope this helps!

Answer:

: fluorine, oxygen, or nitrogen.

Explanation:

Hydrogen bonding occurs only in molecules where hydrogen is covalently bonded to one of three elements: fluorine, oxygen, or nitrogen.

Hydrogen bonding occurs only in molecules where hydrogen is covalently bonded to one of three elements: fluorine, oxygen, or nitrogen. These three elements are so electronegative that they withdraw the majority of the electron density in the covalent bond with hydrogen, leaving the H atom very electron-deficient. The H atom nearly acts as a bare proton, leaving it very attracted to lone pair electrons on a nearby atom.

Answer:

The process of photosynthesis is commonly written as: 6CO2 + 6H2O → C6H12O6 + 6O2. This means that the reactants, six carbon dioxide molecules and six water molecules, are converted by light energy captured by chlorophyll (implied by the arrow) into a sugar molecule and six oxygen molecules, the products.

Answer:

C

Explanation:

running the balloon against your hair

In some plants such as Cactuses, the stem is flattened and green and carries out the function of the leaf. Such a stem, adapted for the manufacture of food is called phylloclade. The leaves here are reduced or modified into spines to lessen the transpiring surface.

This question is mentioning an experiment that is not being described about the volume of the propane gas in an Erlenmeyer before the addition of water.

In this case, since no information is given, it is possible to propose a suggested procedure of how to figure it out via gas laws, specifically, the ideal gas one, since no change is decribed before the addition of water:

[tex]PV=nRT[/tex]

Thus, you can solve for the volume, by dividing both sides by the pressure, so that you will get:

[tex]V=\frac{nRT}{P}[/tex]

Now, to ensure a correct calculation, make sure you have the moles (divide by the molar mass of propane, 44,1 g/mol, if you were given the grams), the temperature in K (add 273.15 if you have degree Celsius), the ideas gas constant as 0.08206 and the pressure in atm, in order to have consistent units.

If you need the volume in milliliters, you will need to multiply the previous answer by 1000 in order to perform the appropriate conversion.

Learn more:

Answer:

(B) SECONDARY ALKYL HALIDE