The mass of an object is described in

alex41 [277]

Hey, lovely! It's a pretty lengthy process but here is a pretty clear video on how to do it. Hope this helps ya!

https://www.khanacademy.org/science/chemistry/chemical-reactions-stoichiome/balancing-chemical-equat...

4 0

3 years ago

The sample of 15.0 g of KCl is dissolved into a solution with a total volume of 250.0 mL. What is the molarity of KCl in the sol

lina2011 [118]

Answer:

0.805 M.

Explanation:

Hello!

In this case, since the molarity of a solution is computing by dividing the moles of solute over the volume of solution in liters (M=n/V), for 15.0 g of potassium chloride (74.55 g/mol) we compute the corresponding moles:

$n=15.0gKCl*\frac{1molKCl}{74.55gKCl}=0.201molKCl$

Next, since the volume is 0.2500 in liters, the molarity turns out:

$M=\frac{0.201mol}{0.2500L} \\\\M=0.805M$

Best regards!

3 0

3 years ago

Write the appropriate symbol for each of the following isotopes: (a) Z 74, A 186; (b) Z 80, A 201; (c) Z 34, A 76; (d) Z 94, A 2

beks73 [17]

Answer: a) $_{74}^{186}\textrm{W}$

b) $_{80}^{201}\textrm{Hg}$

c) $_{34}^{76}\textrm{Se}$

d) $_{94}^{239}\textrm{Pu}$

Explanation:

General representation of an element is given as:_Z^A\textrm{X}

where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons

In an atom, when neutrons or protons are lost or gains, it directly affects the mass number of an atom.

Atomic number is defined as the number of protons or number of electrons that are present in an atom.

It is characteristic of a particular element.

Atomic number = Number of electrons = Number of proton

a) Z 74, A 186: $_{74}^{186}\textrm{W}$

b) Z 80, A 201: $_{80}^{201}\textrm{Hg}$

c) Z 34, A 76: $_{34}^{76}\textrm{Se}$

d) Z 94, A 239.: $_{94}^{239}\textrm{Pu}$

6 0

2 years ago

Which statement is true regarding a titration? It measures the amount of heat given off in combustion reactions. It determines h

exis [7]

C) It determines the concentration of an unknown substance in neutralization reactions.

3 0

2 years ago

Read 2 more answers

Acetylene gas (c2h2) reacts with oxygen gas (o2) to produce carbon dioxide (co2) and water vapor (h2o). how many liters of c2h2

MissTica

According to the balanced equation of the reaction:

2C2H2 + 5O2 → 4CO2 + 2H2O

So we can mention all as liters,

A) as we see that 2 liters of C2H2 react with 5 liters of oxygen to produce 4 liters of CO4 and 2 liters of H2O

So, when we have 75L of CO2

and when we have 2 L of C2H2 reacts and gives 4 L of CO2

2C2H2 → 4CO2

∴ The volume of C2H2 required is:

= 75L / 2

= 37.5 L

B) and, when we have 75 L of CO2

and 4CO2 → 2H2O

∴ the volume of H2O required is:

= 75 L /2
= 37.5 L

C) and from the balanced equation and by the same way:

when 5 liters O2 reacts to give 4 liters of CO2

and we have 75 L of CO2:

5 O2 → 4 CO2

?? ← 75 L

∴ the volume of O2 required is:

= 75 *(5/4)

= 93.75 L

D) about the using of the number of moles the answer is:

no, there is no need to find the number of moles as we called everything in the balanced equation by liters and use it as a liter unit to get the volume, without the need to get the number of moles.

6 0

2 years ago

Read 2 more answers