Which of the following is not a physical change?

Velocity may be expressed in which I f the following units?

velocity is speed and direction so it should be expressed in mph f/s (feet per second) with a direction like North, right, left,

ex) 5mph south

3 0

3 years ago

If the density of ethanol, C2H5OH, is 0.789 g/mL. How many milliliters of ethanol are needed to produce 15.0 g of CO2 according

Svetradugi [14.3K]

Answer:

9.94 mL, the volume of ethanol needed

Explanation:

The reaction is:

C₂H₅OH(l) + 3 O₂(g) → 2 CO₂(g) + 3 H₂O(l)

We convert the mass of the formed product to moles:

15 g . 1mol / 44g = 0.341 moles

2 moles of dioxide are produced by 1 mol of ethanol, in order to stoichiometry.

Therefore, 0.341 moles of CO₂ must be produced by (0.341. 1) / 2 = 0.1705 moles of alcohol.

We convert the moles to mass, and then, the mass to volume by the use of density.

0.1705 mol . 46 g / 1 mol = 7.84 g of ethanol

Ethanol density = Ethanol mass /Ethanol volume

Ethanol volume = Ethanol mass /Ethanol density → 7.84 g /0.789 g/mL =

9.94 mL

7 0

3 years ago

Read 2 more answers

Complete the following table. Tell if the molecule is polar or nonpolar, draw the Lewis dot structure for the molecule, tell wha

andrew11 [14]

The complete table is shown in figure

a) NH3 is polar as the bonds between N and H are polar. Due to asymmetry in the molecule the molecule is polar

The shape of molecule is trigonal pyramidal while its electronic geometry is tetrahedral.

b) CO2: it is a non polar molecule with polar bonds. The molecule becomes non polar as the dipole moment cancel each other. [Dipole moment is a vector quantity]

The shape is linear.

5 0

3 years ago

Read 2 more answers

Using the equations 2 Sr(s) + O₂ (g) → 2 SrO (s) ∆H° = -1184 kJ/mol SrO (s) + CO₂ (g) → SrCO₃ (s) ∆H° = -234 kJ/mol CO₂ (g) → C(

kkurt [141]

<u>Answer:</u> The $\Delta H^o_{rxn}$ for the reaction is 72 kJ.

<u>Explanation:</u>

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction follows:

$2SrCO_3(s)\rightarrow 2Sr(s)+2C(s)+3O_2(g)$ $\Delta H^o_{rxn}=?$