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Dafna11 [192]
3 years ago
9

7. How many significant figures are in the following numbers?

Chemistry
1 answer:
Vlad1618 [11]3 years ago
7 0
There are
A. 6 significant figures
B.5 sig figs
C.2 sig figs
D.5 sig figs
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Show
SIZIF [17.4K]

Answer: 0.9375 g

Explanation:

To calculate the number of moles for given molarity, we use the equation:

\text{Moles of solute}={\text{Molarity of the solution}}\times{\text{Volume of solution (in L)}}     .....(1)

Molarity of HCl solution = 0.75 M

Volume of HCl solution = 25.0 mL = 0.025 L

Putting values in equation 1, we get:

\text{Moles of} HCl={0.75}\times{0.025}=0.01875moles  

CaCO_3(s)+2HCl(aq)\rightarrow CaCl_2(s)+CO_2(g)+H_2O(l)  

According to stoichiometry :

2 moles of HCl require = 1 mole of CaCO_3

Thus 0.01875 moles of HCl will require=\frac{1}{2}\times 0.01875=0.009375moles  of CaCO_3

Mass of CaCO_3=moles\times {\text {Molar mass}}=0.009375moles\times 100g/mol=0.9375g

Thus 0.9375 g of CaCO_3 is required to react with 25.0 ml of 0.75 M HCl

6 0
2 years ago
A hydrogen only spectrum
nikklg [1K]

Answer:

yes

Explanation:

6 0
2 years ago
How much time does it take for light from the center of the galaxy to reach Earth?
Ede4ka [16]

Answer:

Light moves at 300,000 kilometers per second, divide these and you get 500 seconds, or 8 minutes and 20 seconds this is an average number.

Explanation:

3 0
3 years ago
Free-energy change, ΔG∘, is related to cell potential, E∘, by the equationΔG∘=−nFE∘where n is the number of moles of electrons t
mart [117]

Answer:

a)\Delta G=372490 J

b)\Delta G=-568614 J

Explanation:

a) The reaction:

Mg(s) +Fe^{2+}(aq) \longrightarrow Mg^{2+}(aq) + Fe(s)

The free-energy expression:

\Delta G=-n*F*E

E=E_{red}-E_{ox]

The element wich is reduced is the Fe and the one that oxidates is the Mg:

-0.44V=E_{red}-(-2.37V)=1.93V

The electrons transfered (n) in this reaction are 2, so:

\Delta G=-2mol*96500 C/mol * 1.93 V

\Delta G=-372490 J

b) If you have values of enthalpy and enthropy you can calculate the free-energy by:

\Delta G=\Delta H - T* \Delta S

with T in Kelvin

\Delta G=-675 kJ*\frac{1000J}{kJ} - 298K*-357 J/K

\Delta G=-568614 J

7 0
2 years ago
PLEASE! :( Two aqueous solutions of AgNO3 and NaCl are mixed. Which of the following diagrams best represents the mixture? For s
-BARSIC- [3]

Answer:

NaCl + Ag(NO₃) --> Na(NO₃) + AgCl

Explanation:

Chemical equation:

NaCl + Ag(NO₃) --> Na(NO₃) + AgCl

The given reaction represent the double displacement reaction. Anion and cation of both reactant exchange with each others.

The anion of sodium chloride(Cl⁻) combine with cation of silver nitrate Ag⁺ and  NO₃⁻ combine with Na⁺.

The third equation is correct while others are in correct.

Double replacement:

It is the reaction in which two compound exchange their ions and form new compounds.

AB + CD → AC +BD

SORRY CAUSE IDK IF THAT HELPED :(

5 0
3 years ago
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