Is concrete a compound element or mixture?

What characteristic best describes an astroid A. It’s around a planet and it is larger than the planet B. is much smaller than t

coldgirl [10]

The answer is B. Hope this helped

4 0

3 years ago

The electrolysis of water forms H2 and O2. 2H2O 2H2 + O2 What is the percent yield of O2 if 10.2 g of O2 is produced from the de

BigorU [14]

<u>Answer:</u> The percent yield of oxygen gas is 67.53 %.

<u>Explanation:</u>

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

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of water = 17.0 g

Molar mass of water = 18 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{17.0g}{18g/mol}=0.944mol$

For the given chemical equation:

$2H_2O\rightarrow 2H_2+O_2$

By Stoichiometry of the reaction:

2 moles of water produces 1 mole of oxygen gas

So, 0.944 moles of water will produce = $\frac{1}{2}\times 0.944=0.472moles$ of oxygen gas

Now, calculating the mass of oxygen gas from equation 1, we get:

Molar mass of oxygen gas = 32 g/mol

Moles of oxygen gas = 0.472 moles

Putting values in equation 1, we get:

$0.472mol=\frac{\text{Mass of oxygen gas}}{32g/mol}\\\\\text{Mass of oxygen gas}=(0.472mol\times 32g/mol)=15.104g$

To calculate the percentage yield of oxygen gas, we use the equation:

$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Experimental yield of oxygen gas = 10.2 g

Theoretical yield of oxygen gas = 15.104 g

Putting values in above equation, we get:

$\%\text{ yield of oxygen gas}=\frac{10.2g}{15.104g}\times 100\\\\\% \text{yield of oxygen gas}=67.53\%$

Hence, the percent yield of oxygen gas is 67.53 %.

7 0

4 years ago

Read 2 more answers

For each of the following compounds, decide whether the compound's solubility in aqueous solution changes with pH.

stepladder [879]

Answer:

a. pH raises

b. pH neutral

c. pH raises

Explanation:

First of all we need to dissociate these compounds.

Ca(OH)₂ → Ca²⁺ + 2OH⁻

This is the calcium hydroxide, a strong base.

In this case, we are giving OH⁻ to medium, so the pH will be increased.

OH⁻ + H⁺ ⇄ H₂O

Hydroxides will neutralize the protons in order to make water, but if we have many OH, we talk about a basic solution where pH is lower than 7.

b. CuBr → Cu⁺ + Br⁻

This is similar to NaCl, a ionic salt which is neutral.

The ions from this salt, do not make hydrolisis, that's why pH does not change.

c. Ca₃(PO₄)₂ → 3Ca²⁺ + 2PO₄⁻³

Calcium cathion comes from a strong base. It means, that the ion can not make hydrolisis because it is the conjugate weak acid.

Phosphate anion comes from a weak acid, it can gives OH⁻ to medium so pH will increase; the PO₄⁻³ anion is the conjugate strong base of the phosphoric acid, that's why it can react:

PO₄⁻³ + H₂O ⇄ H₂PO⁻² + OH⁻

3 0

3 years ago

A sample of a gas is in a sealed container. The pressure of the gas is 565 torr , and the temperature is 27 ∘C . If the temperat

Radda [10]

Answer:

P₂ = 647 torr

Explanation:

Given data:

Initial pressure = 565 torr

Initial temperature = 27°C

Final temperature = 71°C

Final pressure = ?

Solution:

Initial temperature = 27°C (27+273 = 300 K)

Final temperature = 71°C (71+273 = 344 K)

According to Gay-Lussac Law,

The pressure of given amount of a gas is directly proportional to its temperature at constant volume and number of moles.

Mathematical relationship:

P₁/T₁ = P₂/T₂

Now we will put the values in formula:

565 torr / 300K = P₂/344 K

P₂ = 565 torr × 344 K / 300 K

P₂ = 194360 torr. K /293 K

P₂ = 647 torr

5 0

3 years ago

Please help and explain how to do it need the answer asap, please.

dimulka [17.4K]

Answer:

45 and 20 c2 Or4

Explanation:

8 0

3 years ago