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2 years ago

Which terms are associated with the Cenozoic era: Homo sapiens, mammoth, dinosaur, grass?

Chemistry

1 answer:

abruzzese [7]2 years ago

4 0

Mammoths and dinosaurs lived in the Cenozoic era, and there was also grass. Your answers are Mammoth, dinosaur, grass.

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10 pts) A student titrates a 20.00 mL sample of an aqueous borax solution with 1.03 M H2SO4. If 2.07 mL of acid are needed to re

Natasha2012 [34]

Answer: The molarity of the borax solution is 0.107 M

Explanation:

The neutralization reaction is:

$Na_2B_4O_7.10H_2O+H_2SO_4(aq)\rightarrow Na_2SO_4+4H_3BO_3+5H_2O$

According to neutralization law:

$n_1M_1V_1=n_2M_2V_2$

where,

$n_1$ = basicity of $H_2SO_4$ = 2

$n_2$ = acidity of borax = 2

$M_1$ = concentration of $H_2SO_4$ = 1.03 M

$M_2$ = concentration of borax =?

$V_1$ = volume of $H_2SO_4$ = 2.07ml

$V_2$ = volume of borax = 20.0 ml

Now put all the given values in the above law, we get the molarity of borax:

$(2\times 1.03\times 2.07)=(2\times M_2\times 20.0)$

By solving the terms, we get :

$M_2=0.107M$

Thus the molarity of the borax solution is 0.107 M

7 0

3 years ago

Be sure to answer all parts. Sulfur dioxide is released in the combustion of coal. Scrubbers use lime slurries of calcium hydrox

scoray [572]

<u>Answer:</u> The balanced chemical equation is written below and $\Delta S^o$ for the reaction is -160.6 J/K

<u>Explanation:</u>

When calcium hydroxide reacts with sulfur dioxide, it leads to the formation of calcium sulfate and water molecule.

The chemical equation for the reaction of calcium hydroxide and sulfur dioxide follows:

$Ca(OH)_2(s)+SO_2(g)\rightarrow CaSO_3(s)+H_2O(l)$

To calculate the entropy change of the reaction, we use the equation:

$\Delta S^o_{rxn}=\sum [n\times \Delta S^o_{products}]-\sum [n\times \Delta S^o_{reactants}]$

For the given reaction:

$\Delta S^o_{rxn}=[(1\times \Delta S^o_{CaSO_3(s)})+(1\times \Delta S^o_{H_2O(l)})]-[(1\times \Delta S^o_{Ca(OH)_2(s)})+(1\times \Delta S^o_{SO_2(g)})]$

Taking the standard entropy change values:

$\Delta S^o_{CaSO_3(s)}=101.4Jmol^{-1}K^{-1}\\\Delta S^o_{H_2O(l)}=69.9Jmol^{-1}K^{-1}\\\Delta S^o_{Ca(OH)_2(s)}=83.4Jmol^{-1}K^{-1}\\\Delta S^o_{SO_2(g)}=248.5Jmol^{-1}K^{-1}$

Putting values in above equation, we get:

$\Delta S^o_{rxn}=[(1\times (101.4))+(1\times (69.9))]-[(1\times (83.4))+(1\times (248.5))]\\\\\Delta S^o_{rxn}=-160.6J/K$

Hence, the balanced chemical equation is written above and $\Delta S^o$ for the reaction is -160.6 J/K

3 0

2 years ago

Which metal is most likely to form more than one kind of positively charged ion?

nataly862011 [7]

C. Nickel, hope this helps!

4 0

2 years ago

What is the most likely reason why scientists change a model?

deff fn [24]

A doesn't change the model, that's what google's for, B can be easily used with the current model, and D is ridiculous.

The model of, for example, the atom, has changed over the years with multiple experiment sand multiple models. There was plum pudding, for example, with protons and electrons scattered throughout, until Rutherford's experiments (a new discovery) changed that because he found a dense nucleus.

The answer pops out at you

5 0

3 years ago

What will happen to the chemical equilibrium if MgCl2 is added?

Verizon [17]

The chemical equilibrium will be unaffected

6 0

3 years ago