All categories

2 years ago

When is Roblo..x coming back on? :////

Chemistry

2 answers:

Kryger [21]2 years ago

4 0

I've no idea about it...

Neko [114]2 years ago

4 0

Wdym? It’s back and you can play for free and sign up without paying :^

You might be interested in

Aluminum reacts with iron nitrate to form aluminum nitrate and iron. What is the

Lelechka [254]

The reactants are aluminum and iron nitrate.

5 0

2 years ago

Which of the following is a buffer system? Which of the following is a buffer system? H2CO3(aq) and KHCO3(aq) NaCl(aq) and NaOH(

Readme [11.4K]

Answer:

Explanation:

A buffer is defined as an aqueous mixture of a weak acid and its conjugate base or vice versa.

In the systems:

H₂CO₃(aq) and KHCO₃(aq): Carbonic acid, H₂CO₃, is a weak acid that, in solution with its conjugate pair, HCO₃⁻ make a buffer system.

NaCl(aq) and NaOH(aq): NaCl is a salt and NaOH is a strong base. Thus, this system is not  a buffer system.

H₂O(l) and HCl(aq): Water is a solvent and HCl a strong acid. This is not a buffer system.

HCl(aq) and NaOH(aq): HCl is a strong acid and NaOH a strong base. This is not a buffer system.

NaCl(aq) and NaNO₃(aq): Both NaCl and NaNO₃ are salts and this system is not a buffer system.

3 0

3 years ago

Do plasmids have an importance beyond the practice of genetic engineering?

kozerog [31]

Answer: Yes

Explanation: Plasmids offer a number of unique characteristics that make genetic engineering much more efficient. Plasmids are a type of non-chromosomal DNA. Integrating DNA into a bacterial or other chromosome is far more complex than simply putting DNA into a cell; plasmids make it easier to transport DNA into a cell by eliminating this step.

4 0

2 years ago

Excess magnesium reacts with 165.0 grams of hydrochloric acid in a single displacement reaction.

JulsSmile [24]

Answer:

The volume of hydrogen gas produced will be approximately 50.7 liters under STP.

Explanation:

Relative atomic mass data from a modern periodic table:

H: 1.008;
Cl: 35.45.

Magnesium is a reactive metal. It reacts with hydrochloric acid to produce

Hydrogen gas $\rm H_2$ , and
Magnesium chloride, which is a salt.

The chemical equation will be something like

$\rm ?\;Mg\;(s) + ?\;HCl \;(aq)\to ?\;H_2 \;(g)+ [\text{Formula of the Salt}]$ ,

where the coefficients and the formula of the salt are to be found.

To determine the number of moles of $\rm H_2$ that will be produced, first find the formula of the salt, magnesium chloride.

Magnesium is a group 2 metal. The oxidation state of magnesium in compounds tends to be +2.

On the other hand, the charge on each chloride ion is -1. Each magnesium ion needs to pair up with two chloride ions for the charge to balance in the salt, magnesium chloride. The formula for the salt will be $\rm MgCl_2$ .

$\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ ?\;MgCl_2\;(aq)$ .

Balance the equation. $\rm MgCl_2$ contains the largest number of atoms among all species in this reaction. Start by setting its coefficient to 1.

$\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ {\bf 1\;MgCl_2}\;(aq)$ .

The number of $\rm Mg$ and $\rm Cl$ atoms shall be the same on both sides. Therefore

$\rm {\bf 1\;Mg}\;(s) + {\bf 2\;HCl}\;(aq) \to ?\;H_2 \;(g)+ {1\;\underset{\wedge}{Mg}\underset{\wedge}{Cl_2}}\;(aq)$ .

The number of $\rm H$ atoms shall also conserve. Hence the equation:

$\rm {1\;Mg}\;(s) + {2\;\underset{\wedge}{H}Cl}\;(aq) \to {\bf 1\;H_2 \;(g)}+ {1\;MgCl_2}\;(aq)$ .

How many moles of HCl are available?

$M(\rm HCl) = 1.008 + 35.45 = 36.458\;g\cdot mol^{-1}$ .

$\displaystyle n({\rm HCl}) = \frac{m(\text{HCl})}{M(\text{HCl})} = \rm \frac{165.0\;g}{36.458\;g\cdot mol^{-1}} = 4.52576\;mol$ .

How many moles of Hydrogen gas will be produced?

Refer to the balanced chemical equation, the coefficient in front of $\rm HCl$ is 2 while the coefficient in front of $\rm H_2$ is 1. In other words, it will take two moles of $\rm HCl$ to produce one mole of $\rm H_2$ . $\rm 4.52576\;mol$ of $\rm HCl$ will produce only one half as much $\rm H_2$ .

Alternatively, consider the ratio between the coefficient in front of $\rm H_2$ and $\rm HCl$ is:

$\displaystyle \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}$ .

$\displaystyle n(\text{H}_2) = n(\text{HCl})\cdot \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}\;n(\text{HCl}) = \rm \frac{1}{2}\times 4.52576\;mol = 2.26288\;mol$ .

What will be the volume of that many hydrogen gas?

One mole of an ideal gas occupies a volume of 22.4 liters under STP (where the pressure is 1 atm.) On certain textbook where STP is defined as $\rm 1.00\times 10^{5}\;Pa$ , that volume will be 22.7 liters.

$V(\text{H}_2) = \rm 2.26288\;mol\times 22.4\;L\cdot mol^{-1} = 50.69\; L$ , or

$V(\text{H}_2) = \rm 2.26288\;mol\times 22.7\;L\cdot mol^{-1} = 51.37\; L$ .

The value "165.0 grams" from the question comes with four significant figures. Keep more significant figures than that in calculations. Round the final result to four significant figures.

5 0

3 years ago

Bats and marine mammals are able to locate prey and to communicate by sending and receiving sound waves that echo off surface. E

Nesterboy [21]

I’m pretty sure it’s S

8 0

2 years ago

Read 2 more answers

When is Roblo..x coming back on? :////​

When is Roblo..x coming back on? :////