6. The variable that a scientist changes on purpose to test a hypothesis is the

Dark silicates have a specific gravity of 3.2 to 3.6 and are composed primarily of silica tetrahedral and ________. Select one:

ch4aika [34]

The answer is option e that is e. Iron and magnesium.

Dark silicates have a specific gravity of 3.2 to 3.6 and are composed primarily of silica tetrahedral and iron and magnesium.

Iron and magnesium is a component of dark silicates that have a specific gravity of 3.2 to 3.6.

So the answer is iron and magnesium.

8 0

3 years ago

Read 2 more answers

How many liters of water do we need to add to 5.00 moles to get a 0.648 M solution?

Tanya [424]

Answer: This is a typical acid/base equilibrium problem, that involves the use of logarithms.

Explanation:We assume that both nitric acid and hydrochloric acid dissociate to give stoichiometric

H

3

O

+

.

Moles of nitric acid:

26.0

×

10

−

3

⋅

L

×

8.00

⋅

m

o

l

⋅

L

−

1

=

0.208

⋅

m

o

l

H

N

O

3

(

a

q

)

.

And, moles of hydrochloric acid:

88.0

×

10

−

3

⋅

L

×

5.00

⋅

m

o

l

⋅

L

−

1

=

0.440

⋅

m

o

l

H

C

l

(

a

q

)

.

This molar quantity is diluted to

1.00

L

. Concentration in moles/Litre =

(

0.208

+

0.440

)

⋅

m

o

l

1

L

=

0.648

⋅

m

o

l

⋅

L

−

1

.

Now we know that water undergoes autoprotolysis:

H

2

O

(

l

)

⇌

H

+

O

H

−

. This is another equilibrium reaction, and the ion product

[

H

+

]

[

O

H

−

]

=

K

w

. This constant,

K

w

=

10

−

14

at

298

K

.

So

[

H

+

]

=

0.648

⋅

m

o

l

⋅

L

−

1

;

[

O

H

−

]

=

K

w

[

H

+

]

=

10

−

14

0.648

=

?

p

H

=

−

log

10

[

H

+

]

=

−

log

10

(

0.648

)

=

?

Alternatively, we know further that

p

H

+

p

O

H

=

14

. Once you have

p

H

,

p

O

H

is easy to find. Take the antilogarithm of this to get

[

O

H

−

]

.

Answer link

4 0

3 years ago

How much potential energy an object has depends on the object

riadik2000 [5.3K]

Yea you’re right. You answered your own question lol

5 0

3 years ago

How many orbitals are in the n=3 level

solniwko [45]

The third shell has 3 subshells: the subshell, which has 1 orbital with 2 electrons, the subshell, which has 3 orbitals with 6 electrons, and the subshell, which has 5 orbitals with 10 electrons, for a total of 9 orbitals and 18 electrons.

7 0

3 years ago

Read 2 more answers

Need help with 22 and 24

choli [55]

Answer:

22:

Formular:

$atomic \: mass = \frac{ \sum(isotopic \: mass \times \%abundance)}{100} \\$

substitute:

$atomic \: mass = \frac{(23.985 \times 78.70) + (24.986 \times 10.13) + (25.983 \times 11.17)}{100} \\ \\ = \frac{(1887.620) + (253.108) + (290.230)}{100} \\ \\ = \frac{2430.958}{100} \\ \\ { \boxed{ \boxed{average \: atomic \: mass = 24.3 \: amu}}}$

23:

Same element is represented by same number of protons. 

Answer:

6 protons. 6 protons

7 neutrons. 8 neutrons

6 electrons. 6 electrons

Note: Atoms with same proton number but different mass number are called isotopes

5 0

3 years ago

Read 2 more answers