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3 years ago

What have all living things evolved from?

Chemistry

2 answers:

dedylja [7]3 years ago

3 0

Earlier species thanks to evolution. hope this helped!

artcher [175]3 years ago

3 0

Answer:

Earlier species thanks to evolution. hope this helped out!

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How would your atomic mass prediction have been affected if not all of the water had been evaporated from the calcium carbonate

Yanka [14]

Go to a famlie member, if you can't trust them, trust god. if you cant trust god, BURN IN HELL

6 0

3 years ago

When 0.513 g of biphenyl (c12h10 undergoes combustion in a bomb calorimeter, the temperature rises from 26.3 ?c to 29.7 ?c?

olasank [31]

When 0.514 g of biphenyl (C12H10) undergoes combustion in a bomb calorimeter, the temperature rises from 25.8 C to 29.4 C. Find ⌂E rxn for the combustion of biphenyl in kJ/mol biphenyl. The heat capacity of the bomb calorimeter, determined in a separate experiment, is 5.86 kJ/ C.

<span>The answer is - 6.30 * 10^3 kJ/mol

</span>

3 0

3 years ago

When 0.620 gMngMn is combined with enough hydrochloric acid to make 100.0 mLmL of solution in a coffee-cup calorimeter, all of t

OleMash [197]

Answer:

The enthalpy change during the reaction is -199. kJ/mol.

Explanation:

$Mn(s)+2HCl(aq)\rightarrow MnCl_2(aq)+H_2(g)$

Mass of solution = m

Volume of solution = 100.0 mL

Density of solution = d = 1.00 g/mL

$m=1.00 g/mL\times 100.0 mL = 100 g$

First we have to calculate the heat gained by the solution in coffee-cup calorimeter.

$q=m\times c\times (T_{final}-T_{initial})$

where,

m = mass of solution = 100 g

q = heat gained = ?

c = specific heat = $4.18 J/^oC$

$T_{final}$ = final temperature = $23.1^oC$

$T_{initial}$ = initial temperature = $28.9^oC$

Now put all the given values in the above formula, we get:

$q=100 g \times 4.18 J/^oC\times (28.9-23.1)^oC$

$q=2,242.4 J=2.242 kJ$

Now we have to calculate the enthalpy change during the reaction.

$\Delta H=-\frac{q}{n}$

where,

$\Delta H$ = enthalpy change = ?

q = heat gained = 2.242 kJ

n = number of moles fructose = $\frac{\text{Mass of manganese}}{\text{Molar mass of manganese}}=\frac{0.620 g}{54.94 g/mol}=0.0113 mol$

$\Delta H=-\frac{2.242 kJ}{0.0113 mol }=-199. kJ/mol$

Therefore, the enthalpy change during the reaction is -199. kJ/mol.

8 0

2 years ago

The ksp of yttrium fluoride, yf3, is 8.62 × 10-21. calculate the molar solubility of this compound.

motikmotik

Answer:

The molar solubility of YF₃ is 4.23 × 10⁻⁶ M.

Explanation:

In order to calculate the molar solubility of YF₃ we will use an ICE chart. We identify 3 stages: Initial, Change and Equilibrium and we complete each row with the concentration of change of concentration. Let's consider the solubilization of YF₃.

YF₃(s) ⇄ Y³⁺(aq) + 3 F⁻(aq)

I 0 0

C +S +3S

E S 3S

The solubility product (Ksp) is:

Ksp = [Y³⁺].[F⁻]³= S . (3S)³ = 27 S⁴

$S=\sqrt[4]{Ksp/27} =\sqrt[4]{8.62 \times 10^{-21} /27}=4.23 \times 10^{-6}M$

6 0

3 years ago

What is an experiment?

OLEGan [10]

Answer:

a scientific procedure undertaken to make a discovery, test a hypothesis, or demonstrate a known fact.

6 0

3 years ago