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3 years ago

Most terrestrial plants are members of this Division:

Chemistry

2 answers:

aliina [53]3 years ago

4 0

Answer:

most flowering plants are classified as angiosperms

AURORKA [14]3 years ago

4 0

Answer:

I think the answer is Bryophyta

Explanation:

seedless,non vascular plants that are the closest extant relative of early terrestrial plants

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1. Explain the relationship<br> between Polaris and Earth's tilt

Oduvanchick [21]

Answer:

that it i think

Explanation:

the earth revolves around the Sun once each year and spins on its axis of rotation once each day. This axis of rotation is tilted 23.5 degrees relative to its plane of orbit around the Sun. The axis of rotation is pointed toward Polaris the North Star. As the Earth orbits the Sun the tilt of Earth’s axis stays lined up with the North Star.

7 0

4 years ago

Tris is a molecule that can be used to prepare buffers for biochemical experiments. It exists in two forms: Tris (a base) and Tr

ale4655 [162]

Solution :

For the reaction :

$\text{TrisH}^+ + H_2O \rightarrow \text{Trish}^- + H_3O^+$

we have

$Ka = \frac{[\text{Tris}^- \times H_3O]}{\text{Tris}^+}$

$=\frac{x^2}{0.02 -x}$

$=8.32 \times 10^{-9}$

Clearing $x$ , we have $x = 1.29 \times 10^{-5} \text{ moles of acid}$

So to reach $\text{pH} = 7.8 (\text{pOH}= 14-7.8=6.2)$ , one must have the $\text{OH}^-$ concentration of the :

$\text{[OH}^-]=10^{-pOH} = 6.31 \times 10^{-7} \text{ moles of base}$

So we can add enough of 1 M NaOH in order to neutralize the acid that is calculated above and also adding the calculated base.

$\text {n NaOH}=1.29 \times 10^{-5}+6.31 \times 10^{-7}$

$= 1.35 \times 10^{-5} \text{ moles}$

Volume NaOH $= 1.35 \times 10^{-5} \text{ moles} \times \frac{1000 \text{ mL}}{1 \text{ mol}} = 0.0135 \text{ mL}$

Tris mass $H^+ = 0.02 \text{ mol} \times 157.6 \text{ g/mol}=3.152 \text{ g}$

Now to prepare the said solution we must mix:

$3.152 \text{ g Tris H} + 0.0135 \text{ mL NaOH} \ 1 M$ gauge to 1000 mL with water.

3 0

3 years ago

What is the concentration of an unknown Mg(OH)2 solution if it took an average of 15.4mL of

vova2212 [387]

Answer:

0.077M

Explanation:

Step 1:

The balanced equation for the reaction. This is given below:

2HCl + Mg(OH)2 —> MgCl2 + 2H2O

From the balanced equation above,

The mole ratio of the acid (nA) = 2

The mole ratio of the base (nB) = 1

Step 2:

Data obtained from the question.

Concentration of base Cb =...?

Volume of base (Vb) = 10mL

Concentration of acid (Ca) = 0.1M

Volume of acid (Va) = 15.4mL

Step 3:

Determination of the concentration of the base, Mg(OH)2.

The concentration of the base can be obtained as follow:

CaVa/CbVb = nA/nB

0.1 x 15.4 /Cb x 10 = 2/1

Cross multiply to express in linear form

Cb x 10 x 2 = 0.1 x 15.4

Divide both side by 10 x 2

Cb = (0.1 x 15.4) /(10 x 2)

Cb = 0.077M

Therefore, the concentration of the base, Mg(OH)2 is 0.077M

7 0

3 years ago

Suppose water did not form hydrogen bonds.

Vilka [71]

-70°C

Sink

little

hydrogen bonding

Explanation:

Completing the statements:

Water's boiling point would have been close to -70°C. Ice would sink in water. Water would release little heat to warm land during the winter. Ice is less dense than water because of the hydrogen bonding that forms a hexagonal structure in water.

The unique property of water is as a result of its hydrogen bonding. Water is a polar covalent compound. Like most covalent compound, water would have naturally had a very low boiling point.

The intermolecular forces all hydrogen bonding gives water its unique nature.

Hydrogen bond is formed by an attraction between hydrogen one water water molecule and more electronegative atom on another molecule usually oxygen, nitrogen and fluorine.

They form very strong intermolecular interaction responsible for the behavior of water.

The higher specific heat capacity of water is due to this bond. It absorbs a lot of heat and does not release them on time. This causes water release heat during winter.

Water has a hexagonal shape or structure linking each molecules.

learn more;

Hydrogen bonding brainly.com/question/10602513

#learnwithBrainly

5 0

3 years ago

Read 2 more answers

Which statement is true if the Hrxn of a reaction is positive?

erma4kov [3.2K]

I think it is b..................................................

7 0

4 years ago

Read 2 more answers