Particle quantity/number of Cu(NO3)2

1. 2KCIO3, -- 2KCI + 302 How many moles of O2 will be produced from 2.25 moles of KCIO3?

Scilla [17]

Answer:

3.375moles of O₂

Explanation:

The reaction expression is given as;

2KClO₃ → 2KCl + 3O₂

Number of moles of KClO₃ = 2.25moles

Now;

To find the number of moles of O₂ produced we use known number of moles.

So;

2 mole of KClO₃ will produce 3 moles of O₂

2.25moles of KClO₃ will produce $\frac{2.25 x 3}{2}$ = 3.375moles of O₂

8 0

3 years ago

How many atoms are in 25.00 g of B?

klio [65]

Answer:

There are 1.393 x 10²⁴ atoms in 25.00 g of B.

Explanation:

Hey there!

We are given a value, in grams, that we need to convert to a number of atoms.

We can convert grams to atoms by using Avogadro's Number ( $N_A$ ). This number is equivalent to $6.022 \times 10^{23}$ .

This number can be used to convert any values to:

atoms
molecules
formula units
moles

In order to do this problem, we will need to use dimensional analysis (DA). This process allows us to convert from grams to atoms.

We need to set up our ratios in order to work this out. We can use a periodic table to help us through this next part of the problem.

1. Locating the number of moles of B in the sample

We first need to find the amount of moles of boron (B) there are in the sample.

Checking a periodic table, the atomic mass in atomic mass units (amu) is 10.81 amu.

Atomic mass units can easily be converted to grams and these units can be used interchangeably.

Therefore, for each atom of boron, it weighs 10.81 grams to us. This is equivalent to the mass of one mole of boron.

To find the number of moles, we have two possible ratios we can use:

$\displaystyle \frac{1 \ mole \ B}{10.81 \ grams \ B}$

$\displaystyle \frac{10.81 \ grams \ B}{1 \ mole \ B}$

These ratios mean the same thing, but we need to convert our final unit to moles.

We are given a sample in grams, and when dividing our units, we need to keep moles.

Since the first portion of our expression is in grams, we need to have grams in the bottom of our expression.

$\displaystyle 25.00 \ \text{grams B} \ \times \frac{1 \text{mole B}}{10.81 \ \text{grams B}}$

We can now simplify the expression. Our grams B unit will cancel out, so we are therefore left with moles B remaining.

2. Locating the number of atoms in the sample

Now with our equation, we can convert our number of moles that would be solved if we stopped with the above. However, we need to convert to atoms.

We use Avogadro's number and create a ratio with that of moles.

$\displaystyle \frac{6.022 \times 10^{23}\text{atoms}}{1 \text{mole B}}$

$\displaystyle \frac{1 \text{mole B}}{6.022 \times 10^{23} \text{atoms}}$

We need to cancel out our moles and end with atoms, so we must have moles in the denominator. Therefore, we use the first ratio.

Using our previous expression, we multiply by this new ratio and solve the expression.

$\displaystyle 25.00 \ \text{grams B} \ \times \frac{1 \text{mole B}}{10.81 \ \text{grams B}} \ \times \frac{6.022 \times 10^{23}\text{atoms}}{1 \text{mole B}}$

This expression can now be operated. You will need a calculator to perform this calculation.

Our numerator is:

$[(25.00 \times 1 \times (6.022 \times 10^{23})]$

Plugging this into a calculator, we get:

$1.5055 \times 10^{25}$

Our denominator is:

$(1 \times 10.81 \times 1)$

This simplifies to:

$10.81$

Dividing our numerator and denominator:

$\displaystyle \frac{1.5055 \times 10^{25}}{10.81}$

Plugging this into a calculator, we get:

$1.392691952 \times 10^{24}$

3. Simplifying with significant figures

Now, we need to take into account that we have significant figures. We are given this original value:

$25.00$

This value has four significant figures, which means we need to round our value we received above to four significant figures.

$\approx 1.393$

Our units are added as well as our scientific notation:

$1.393 \times 10^{24} \ \text{atoms of B}$

Therefore, our final answer is choice A.

8 0

3 years ago

Kaia, a chemical engineering graduate, has documented all titration procedures in her project report. She refers to this report

vagabundo [1.1K]

Answer:

The correct option is;

d. Explicit knowledge

Explanation:

Explicit knowledge is the knowledge that can be easily articulated documented stored in a retrieval system accesses, transmitted and shared with others

Tacit knowledge is the skill developed by an individual based on actual experience such that such knowledge comprise of both facts and perspectives

Hence explicit knowledge and tacit knowledge are complementary

The operations performed by Kaia include documentation, storing in a retrieval system (her project report) and accessing what she documented, this is an example of explicit knowledge.

7 0

3 years ago

Explain how boiling and evaporating are alike and how they are differant

julsineya [31]

Answer:

The main difference between evaporation and boiling are : 1. Evaporation takes place at all temperatures, while boiling occurs at a particular temperature. 2. Evaporation takes place from the surface, whereas the entire liquid boils. 3. Evaporation can occur using the internal energy of the system, while boiling requires an external source of heat.

7 0

3 years ago

Changes is sea level can result from water being locked inside a

s2008m [1.1K]

Seawater becomes warmer it expands. Heat in the upper layer of the ocean is released quickly into the atmosphere. However, heat absorbed by the deeper layers of the ocean will take much longer to be released and therefore, be stored in the ocean much longer and have significant impacts on future ocean warming.

An increase in freshwater inputs from mountain glaciers, ice sheets, ice caps, and sea ice, as well as other atmospheric and hydrologic cycles due to rising global surface and ocean temperatures

6 0

3 years ago