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gayaneshka [121]

4 years ago

14

A student needs to determine the volume occupied by a gas in a 125 mL flask using the experimental setup described in the proced

ure. The student measures the volume of the flask to be 159 mL to the top of the flask. The student measures the volume of the flask with a stopper in it to be 142 mL. The student performs the experiment by reacting the strip of magnesium with 5 mL of HCl solution. What is the volume of the flask occupied by the hydrogen gas?

1 answer:

Yuki888 [10]4 years ago

6 0

Answer:

It would appear that the H2 gas is collected in a stoppered flask. Therefore, the volume of the gas is 138 mL minus the 5 mL occupied by the HCl, or 133 mL.

Explanation:

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ser-zykov [4K]

Nonmetallic binds are commonly

7 0

3 years ago

Gold has an atomic weight of 196.97 g/mol, and a density of 19.3 g/cm3. Approximately how many atoms are in a spherical gold nan

ale4655 [162]

<u>Answer:</u> The number of atoms in spherical gold nano particle are $26.918\times 10^4$

<u>Explanation:</u>

To calculate the volume of sphere, we use the equation:

$V=\frac{4}{3}\pi r^3$

where,

r = radius of the sphere = $10nm=10^{-6}cm$ (Conversion factor: $1nm=10^{-7}cm$ )

Putting values in above equation, we get:

$V=\frac{4}{3}\times 3.14\times (10^{-6})^3\\\\V=4.19\times 10^{-18}cm^3$

To calculate mass of of the substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Volume of gold = $4.19\times 10^{-18}cm^3$

Density of gold = $19.3g/cm^3$

Putting values in above equation, we get:

$19.3g/cm^3=\frac{\text{Mass of gold}}{4.19\times 10^{-18}}\\\\\text{Mass of gold}=8.0867\times 10^{-17}g$

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Mass of gold = $8.8067\times 10^{-17}g$

Molar mass of gold = 196.97 g/mol

Putting values in above equation, we get:

$\text{Moles of gold}=\frac{8.8067\times 10^{-17}g}{196.97g/mol}=4.47\times 10^{-9}moles$

According to mole concept:

1 mole of an element contains $6.022\time 10^{23}$ number of atom

So, $4.47\times 10^{-19}$ moles of gold will contain = $4.47\times 10^{-19}\times 6.022\times 10^{23}=26.918\times 10^4$ number of atoms.

Hence, the number of atoms in spherical gold nano particle are $26.918\times 10^4$

8 0

3 years ago

The information below describes a redox reaction.

Mnenie [13.5K]

Answer:

The answer to your question is the first option

Explanation:

Just remember that to balance using this method,

first look for the elements that change their oxidation number, and

later count the number of electrons that changed,

later identify which element oxidazes and which reduces and

finally cross the number of electrons that change in each semireaction and write these numbers in the main reaction.

2Cr⁺³ (aq) + 6Cl⁻ (aq) ⇒ 2Cr(s) + 3Cl₂ (g)

2 Cr 2

6 Cl 6

5 0

4 years ago

Q#5 Balance and list the coefficients from reactants to products.

skad [1K]

A. $2Fe_2O_3(s) +3C(s)$ → $4Fe(s) + 3CO_2(g)$

B. $2Al(s) + 3FeO(s)$ → $Fe(s) + 3Al_2O_3(s)$

C. $2Al(s) +3H_2SO_4(aq)$ → $Al_2(SO_4)_3(aq) + 3H_2(g)$

What is a balanced chemical equation?

An equation that has an equal number of atoms of each element on both sides of the equation is called a balanced chemical equation.

A. $2Fe_2O_3(s) +3C(s)$ → $4Fe(s) + 3CO_2(g)$

B. $2Al(s) + 3FeO(s)$ → $Fe(s) + 3Al_2O_3(s)$

C. $2Al(s) +3H_2SO_4(aq)$ → $Al_2(SO_4)_3(aq) + 3H_2(g)$

Learn more about the balanced chemical equation here:

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8 0

2 years ago

Read 2 more answers

With all the coefficient set to 1, how can you tell that the equation is not balanced?

murzikaleks [220]

Answer:

Well for any equation if all the coefficients are set to 1, this might result in unequal numbers of atoms of the same element on both sides

Explanation:

For example:

$A+B---->B_{2} + A_{2}$ (for this equation all the coefficient (the number before element) are 1 but you can clearly see it is not balanced because one side has 1 A atom and other side has 2 B atoms....therefore we need to balance em.

$2A+2B-----> A_{2} + B_{2}$ Here both atoms are balanced.

7 0

3 years ago