What is a defining trait of all minerals

An exothermic reaction is what<br> energy.

leonid [27]

Answer:

An exothermic reaction releases energy. Endothermic takes in energy.

Explanation:

7 0

2 years ago

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What forces hold network solids together?

mezya [45]

Answer:

Covalent solids, also called network solids, are solids that are held together by covalent bonds. As such, they need localized electrons (shared between the atoms) and therefore the atoms are arranged in fixed geometries. Distortion far from this geometry can only occur through a breaking of covalent sigma bonds.

Pls help i need one more brainly to rank up. And have a great day :D

5 0

3 years ago

Calculate the volume of the acid solution and the volume of the conjugate base solution that would be needed to prepare a buffer

bogdanovich [222]

Answer:

Explanation:

This can be contradictory, depending on whether the 0.1 M

is the total species concentration or the concentration of each of the two components. I'll consider this to be the former...

VA− = 9.125 mL

VHA = 15.875 mL

The Henderson-Hasselbalch equation is:

pH = pKa + log [A−][HA]

We have a pH 4.5

solution of acetic acid and acetate, so from there we can get the ratio of weak acid to conjugate base:

[A−][HA]=10

pH − pKa = 104.5 − 4.74 = 0.5754

Now, if the total concentration is

0.10 M , then:

[HA] + [A−] 0.5754

[HA] = 0.10 M

⇒[HA] = 0.10 M 1.0000 +0.5754

= 0.0635 M

−−−−−−−−

⇒[A−] = 0.0365 M

−−−−−−−−

and these concentrations are AFTER mixing. Since the total volume is 50 mL , or 0.050 L, the mols of each component (which are constant!) are:

nA − = 0.0365 molL × 0.050L =

0.001825 mols

−−−−−−−−−−−−

nHA = 0.0635 molL × 0.050L =

0.003175 mols

−−−−−−−−−−−−

So, if both of the starting concentrations were

0.20 M, we can find the volume they each start with:

VA − = 1 L0.20mols

A− × 0.001825mols A− = 0.009125 L = 9.125 mL

−−−−−−−−

VHA = 1 L 0.20 mols HA × 0.003175

mols HA = 0.015875 L = 15.875 mL

−−−−−−−−−

And this should make sense, because the total starting volume is

25.000 mL , the total ending volume is twice as large; the total species concentration is half the concentration that both species started with.

6 0

2 years ago

What phenomenon in nature do scientists use to define the length of a meter? Why is this a better definition than “the length of

sergey [27]

Answer:

The natural phenomenon used to describe the length of a meter is the speed of light. The length of a meter is the length a light path travels in 1/(299792458) seconds through a vacuum.

The definition is better due to the uncertainty involved in the use of the length of a standard meter stick because the length of the meter stick could change due to atmospheric conditions from place to place

Explanation:

8 0

3 years ago

What is the percent of Cr in Cr2O3

IgorLugansk [536]

The percentage of Chromium in Chromium Oxide is calculated as follow,

Step 1:
Calculate Molar mass of Cr₂O₃,
Cr = 51.99 u
O = 16 u
So,
2(51.99) + 3(16) = 103.98 + 48 = 151.98 u

Step 2:
Secondly divide molar mass of only chromium with total mass of Cr₂O₃ and multiply with 100.
i.e.
= $\frac{103.98}{151.98}$ × 100

= 68.41 %
So, the %age composition of chromium in chromium oxide is 68.41 %.

5 0

2 years ago

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