A B C D ............

Based on solubility rules what ions in water might interfere with the analysis of calcium ions by precipitation of calcium carbo

Pavlova-9 [17]

First, we must know what happens in the precipitation reaction. This type of reaction is a double replacement reactions. It is consists of two reactant compounds which interchange cations and anions to form two products. One of the products is an insoluble solid called a precipitate. For the precipitation of CaCO₃, there are two consecutive reactions involved:

1. Slaking of quicklime, CaO
CaO + H₂O ⇒ Ca(OH)₂

2. Precipitation
Ca(OH)₂ + CO₂ ⇒ CaCO₃ + H₂O

The ions that make up the H₂O molecule are H⁺ and OH⁻. According to solubility rules, the cation (positively charged ion) is likely to be attracted to an anion (negatively charged ion). Together, they form an ionic bond. This type of bond is when there is a complete transfer of electrons between the two. The Ca²⁺ cation lacks 2 electrons, while the anion OH⁻ has an excess 1 electron. In order to be stable, 1 Ca²⁺ ion and 2 OH⁻ ions must combine.

Therefore, the answer is OH⁻ ion.

6 0

3 years ago

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A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or neither will occur. S

Burka [1]

Answer:

Solution A: crenation

Solution B: hemolysis

Solution C: hemolysis

Solution D: crenation

Solution E: crenation

Explanation:

Hemolysis is the rupturing of red blood cells, which results in the release of hemoglobin (from within the red blood cells) into the plasma. If a red blood cell is placed in a hypotonic solution, water will flow into the cell, the cell will swell and hemolysis will.

Crenation: when a red blood cell is placed in a hypertonic solution (such as highly saline solution), the red blood cell will lose water(osmosis) and will shrink in size. The red blood cell has undergone crenation.

In order for a red blood cell to prevent from undergoing hemolysis or crenation, the cell must be placed in an isotonic solution, i.e either in 0.9% (m/v) NaCl solution or 5% glucose solution

Solution B and Solution C are hypotonic solution, thus red blood cell has undergone hemolysis.
Solution A, D and E are hypertonic solution. thus red blood cell has undergone crenation

8 0

3 years ago

A rubber balloon was filled with helium at 25.0˚C and placed in a beaker of liquid nitrogen at -196.0˚C. The volume of the cold

Ksenya-84 [330]

Answer:

The volume of helium at 25.0 °C is 60.3 cm³.

Explanation:

In order to work with ideal gases we need to consider absolute temperatures (Kelvin). To convert Celsius to Kelvin we use the following expression:

K = °C + 273.15

The initial and final temperatures are:

T₁ = 25.0 + 273.15 = 298.2 K

T₂ = -196.0 + 273.15 = 77.2 K

The volume at 77.2 K is V₂ = 15.6 cm³. To calculate V₁ in isobaric conditions we can use Charle's Law.

$\frac{V_{1}}{T_{1}} =\frac{V_{2}}{T_{2}} \\V_{1}=\frac{V_{2}}{T_{2}} \times T_{1}=\frac{15.6cm^{3} }{77.2K} \times 298.2K=60.3cm^{3}$

3 0

3 years ago

A small cube of iron and a large flat sheet of iron contain the same volume. Which one will completely rust first? Explain why.

Hunter-Best [27]

The flat sheet will completely rust before the iron cube. Since they both have the same volume, the flat sheet has more surface area than the small cube. This means more particles are exposed on the flat sheet that can react in a chemical reaction.

4 0

3 years ago

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Consider a sample of a hydrocarbon (a compound consisting of only carbon and hydrogen) at 0.959 atm and 298 K. Upon combusting t

Masja [62]

Answer:

Molecular formula of hydrocarbon is: C₂H₆

Explanation:

The combusting of the hydrocarbon:

CxHy + O₂ → CO₂ + H₂O

Using gas law to obtain molar mass of the gas mixture (CO₂ + H₂O):

P/RT = n/V

Where:

P is pressure (1,208 atm)

R is gas constant (0,082 atmL/molK)

T is temperature (375 K)

n/V = 0,0393 mol/L

1,1128 g/L ÷ 0,0393 mol/L = 28,32 g/mol

Thus, average molecular weight is:

28,32 g/mol = 44,01 g/mol X + 18,02 g/mol Y

1 = X + Y

Where X is CO₂ molar percentage and Y is H₂O molar percentage.

Solving:

X = 0,397

Y = 0,603

39,7% H₂O

60,3% CO₂

With this proportion you can obtain ratio CO₂:H₂O thus:

60,3/39,7 = 1,52 So, 2 CO₂: 3H₂O

The moles of the hydrocarbon are:

PV/RT = n

P (0,959 atm)

V ( 1/5 of final volume)

T (298K)

n = 7,85x10⁻³ mol

The moles of CO₂ are:

0,0393 mol × 2 mol CO₂/ 5 mol total =0,01572.

Ratio of CO₂:CxHY =

0,01572 : 7,85x10⁻³ 2 CO₂: 1 CxHY

Doing:

1 CxHy + O₂ → 2 CO₂ + 3 H₂O

By mass balance:

1 C₂H₆ + 7/2 O₂ → 2 CO₂ + 3 H₂O

Thus, molecular formula of hydrocarbon is: C₂H₆

I hope it helps!

7 0

3 years ago

A B C D ............​

A B C D ............