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Tatiana [17]
3 years ago
6

Which of the following statements is true?

Chemistry
1 answer:
12345 [234]3 years ago
8 0

Answer:

c. Hfus is always negative.

Explanation:

Because energy is released when fusing solids

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Do the number of moles of a gas impact the pressure of a gas?
lapo4ka [179]
Yes. Avogadro Law gives the relationship between volume and amount when pressure and temperature are held constant. Remember amount is measured in moles. This means the gas pressure inside the container will increase (for an instant), becoming greater than the pressure on the outside of the walls.
6 0
3 years ago
A 99.8 mL sample of a solution that is 12.0% KI by mass (d: 1.093 g/mL) is added to 96.7 mL of another solution that is 14.0% Pb
andre [41]

Answer:

m_{PbI_2}=18.2gPbI_2

Explanation:

Hello,

In this case, we write the reaction again:

Pb(NO_3)_2(aq) + 2 KI(aq)\rightarrow PbI_2(s) + 2 KNO_3(aq)

In such a way, the first thing we do is to compute the reacting moles of lead (II) nitrate and potassium iodide, by using the concentration, volumes, densities and molar masses, 331.2 g/mol and 166.0 g/mol respectively:

n_{Pb(NO_3)_2}=\frac{0.14gPb(NO_3)_2}{1g\ sln}*\frac{1molPb(NO_3)_2}{331.2gPb(NO_3)_2}  *\frac{1.134g\ sln}{1mL\ sln} *96.7mL\ sln\\\\n_{Pb(NO_3)_2}=0.04635molPb(NO_3)_2\\\\n_{KI}=\frac{0.12gKI}{1g\ sln}*\frac{1molKI}{166.0gKI}  *\frac{1.093g\ sln}{1mL\ sln} *99.8mL\ sln\\\\n_{KI}=0.07885molKI

Next, as lead (II) nitrate and potassium iodide are in a 1:2 molar ratio, 0.04635 mol of lead (II) nitrate will completely react with the following moles of potassium nitrate:

0.04635molPb(NO_3)_2*\frac{2molKI}{1molPb(NO_3)_2} =0.0927molKI

But we only have 0.07885 moles, for that reason KI is the limiting reactant, so we compute the yielded grams of lead (II) iodide, whose molar mass is 461.01 g/mol, by using their 2:1 molar ratio:

m_{PbI_2}=0.07885molKI*\frac{1molPbI_2}{2molKI} *\frac{461.01gPbI_2}{1molPbI_2} \\\\m_{PbI_2}=18.2gPbI_2

Best regards.

5 0
3 years ago
Read 2 more answers
Determina el pH del café cuya concentración de H+ es de 0.00001M
lara31 [8.8K]

Answer:

5

Explanation:

Given parameters:

Hydrogen ion concentration  =  0.00001M

Unknown:

pH of the solution =?

Solution:

The pH is used to estimate the degree of acidity or alkalinity of a solution. To solve for pH of any solution, we use the expression below;

          pH  = -log [H⁺]

[H⁺] is the hydrogen ion concentration

        pH  = -log (1 x 10⁻⁵)

      pH = -(-5) = 5

4 0
3 years ago
Which one is a true statement about endothermic reactions? a: More heat is given off than is put into the reaction. b :The react
Setler [38]
A because it gets hot
7 0
3 years ago
What design element of an astronaut's spacesuits protects him or her from micrometeoroids, which are tiny bits of space debris t
leonid [27]

Answer:

Tough outer shell

Explanation:

Three types of space suits based on their purpose are IVA (Intravehicular activity), EVA (extravehicular activity), and IEVA (intra/extravehicular activity)

Space suits have an outer layer known as the Integrated Thermal Micrometeoroid Garment also known as the TMG or ITMG

The functions of the TMG includes the provision of an insulation medium to the wearer of the suit thereby preventing loss of heat and keeping the wearer warm, protect the wearer from solar radiation which are harmful as well as from Micrometeoroid and debris orbiting in space known as MMOD

The outermost layer of the EMU TMG suits is white Ortho-Fabric that consists of Nomex, Kevlar and Gore-Tex, making it fire resistant, very strong and very tough, and water proof as well as breathable.

3 0
3 years ago
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