Select the answer that CANNOT be used to fill in the blank in the following sentence:

A student carefully drops a 9.0 g solid Zn pellet initially at 50.0°C into an insulated cup containing 30.0 g of water at 27.8°C

jekas [21]

Answer: choice B

Explanation: Heat flows from high to low. After you convert the Celsius into kelvin the Zn pellet has 323K and the water has 301K which results the transfer of the heat energy of the pallet to the water. ( you don’t have to convert, but it just make it easier) hope this helped you :)

3 0

3 years ago

Read 2 more answers

Which ion has the same electron configuration as an atom of He?

mariarad [96]

Answer;

H- (negatively charged hydrogen ion)

Explanation;

The hydrogen ion has the same electron configuration as an atom of Helium. -Hydrogen ion is formed when a hydrogen atom loses or gains an electron. A positively charged ion is formed when hydrogen atom loses an electron (remaining with zero electrons) while a negatively charged ion (H-) is formed when a hydrogen atom gains an electron thus having 2 electrons.

-Helium atom has two electrons, therefore, it is similar with an negatively charged hydrogen.

3 0

3 years ago

Read 2 more answers

A solution is to be prepared with a sodium ion concentrationof

Lina20 [59]

Answer : The mass of sodium sulfate needed is 5.7085 grams.

Explanation : Given,

Concentration of sodium ion = 0.148 mol/L

Volume of solution = 2.29 L

Molar mass of sodium sulfate = 142 g/mole

First we have to determine the moles of sodium ion.

$\text{Concentration of sodium ion}=\frac{\text{Moles of sodium ion}}{\text{Volume of solution}}$

$0.184mol/L=\frac{\text{Moles of sodium ion}}{2.29L}$

$\text{Moles of sodium ion}=0.08035mole$

Now we have to calculate the moles of sodium sulfate.

The balanced chemical reaction will be,

$Na_2SO_4\rightarrow 2Na^++SO_4^{2-}$

As, 2 moles of sodium ion produced from 1 moles of $Na_2SO_4$

So, 0.08035 moles of sodium ion produced from $\frac{0.08035}{2}=0.040175$ moles of $Na_2SO_4$

Now we have to calculate the mass of sodium sulfate.

$\text{Mass of }Na_2SO_4=\text{Moles of }Na_2SO_4\times \text{Molar mass of }Na_2SO_4$

$\text{Mass of }Na_2SO_4=0.040175mole\times 142g/mole=5.7085g$

Therefore, the mass of sodium sulfate needed is 5.7085 grams.

3 0

4 years ago

3 Cu + 8HNO3 g 3 Cu(NO3)2 + 2 NO + 4 H2O

Ksivusya [100]

Considering the reaction stoichiometry, the amount of moles of NO that is produced when 27 moles of HNO₃ react is 6.75 moles.

<h3 /><h3>Reaction stoichiometry</h3>

The balanced reaction is:

3 Cu + 8 HNO₃ → 3 Cu(NO₃)₂ + 2 NO + 4 H₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Cu: 3 moles
HNO₃: 8 moles
Cu(NO₃)₂: 3 moles
NO: 2 moles
H₂O: 4 moles

<h3>Amount of moles of NO produced</h3>

It is possible to determine the the amount of moles of NO produced by a rule of three: if by stoichiometry 8 moles of HNO₃ produce 2 moles of NO, if 27 moles of HNO₃ react how many moles of NO will be formed?

$amount of moles of NO=\frac{27 moles of HNO_{3} x 2 moles of NO}{8 moles of HNO_{3}}$