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2 years ago

A mixture contains 3.64g nacl, 2.87g nh4cl, and 4.13g of sio2. what is the percent by mass of nh4cl

1 answer:

8 0

<span>Total mass = 3.64 + 2.87 + 4.13 = 10.64 g Mass percent of NH4Cl = (mass of NH4Cl/ Total mass) x 100 = (2.87 g/10.64g) x 100 = 27.0 % mass of NH4Cl</span>

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A quantity of 85.0 mL of 0.900 M HCl is mixed with 85.0 mL of 0.900 M KOH in a constantpressure calorimeter that has a heat capa

bogdanovich [222]

Explanation:

The given data is as follows.

$V_{1}$ = 85.0 ml, $M_{1}$ = 0.9 M

$V_{2}$ = 85.0 ml, $M_{1}$ = 0.9 M

Hence, number of moles of HCl and KOH will be the same because both the solutions have same volume and molarity.

So, No. of moles = Molarity × Volume

= $0.9 M \times 0.085 L$ (as 1 L = 1000 ml so, 85 ml = 0.085 L)

= 0.076 mol

As 1 mole gives 56.2 kJ/mol of heat of neutralization. Hence, calculate the heat of neutralization given by 0.076 moles as follows.

$56.2 kJ/mol \times 0.076 mol$

= 4.271 kJ

or, = 4271 J (as 1 kJ = 1000 J)

Therefore, heat released = - heat of gained by calorimeter

Since, it is given that density of the solution is similar to the density of water which is 1 g/ml.

Hence, mass of HCl = density × Volume of HCl

= 1.00 g/ml × 85.0 ml

= 85 g

Similarly, mass of KOH = = density × Volume of HCl

= 1.00 g/ml × 85.0 ml

= 85 g

Hence, total mass of the solution = 85 g + 85 g

= 170 g

Also, q = $mC \Delta T$

4271 J = $170 g \times 325 J/^{o}C \times (T_{f} - 18.24)^{o}C$

0.0773 = $T_{f} - 18.24$

$T_{f}$ = $18.317^{o}C$

Thus, we can conclude that final temperature of the mixed solution is $18.317^{o}C$ .

6 0

2 years ago

The hybrid orbital set used by the central atom in h2co is ________. the hybrid orbital set used by the central atom in h2co is

Feliz [49]

The Lewis structure for H₂CO is shown in the attached picture. The central atom is the carbon. However, I'm not sure which bond you're referring to. There can be two answers. The two C-H bonds are sp³ hybridized because it is a single bond. The C=O bond is sp² hybridized because it is a double bond.

5 0

2 years ago

The table shows columns that Brenda uses for her notes on the properties of elements. Her notes state that some elements can rea

skad [1K]

Answer:

<u>in the columns for metals and for metalloids</u>

Explanation:

There are six elements that are always classified as metalloids: boron, silicon, germanium, arsenic, antimony, and tellurium. Pollonium is also, generally, classified as a metalloid,

Metalloids have intermediate electronegativity values (in between that of metals and nonmetals), which is responsible for some similarities (or in between properties) with metals and some similarites with non metals.

An example of such properties that metals and metalloids have in common is that they have relative high melting points. Metalloids are all solid at room temperature, such as most metals.

Other property that both metals and metalloids share is that they can react with oxygen to form oxides that are amphoteric.

Amphoteric compounds are substances that can behave as a base or as an acid, depending on the other compound with which they react.

For instance, among metal oxides, aluminum hydroxide, Al(OH)₃, will act as a base when reacts with hydrochloric acid, HCl, and will react as an acid when reacts with sodium hydroxide, NaOH.

The oxides of metalloids are usually amphoteric.

8 0

2 years ago

Read 2 more answers

Water flows over Niagara Falss at the average rate of 2,400,000 kg/s, and the average height of the falls is about 50 m. Knowing

liberstina [14]

Answer:

1. 176 × 10^12 W ; 78400000000

Explanation:

Given the following :

Fall rate = 2,400,000kg/s

Average height of fall = 50m