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3 years ago

All atoms of an element always have the same number of question 4 options: electrons protons electrons neutrons save

1 answer:

7 0

All atoms of an element always have the same number of protons (the positively charged subatomic particle).

Isotopes of the element differ in the mass which means that they differ in the number of the neutrons (which are the subatomic particles having no charge).

At neutral state only will the number of protons be equal to the number of electrons in an atom.

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2.00 L of a gas is collected at 25.0°C and 745.0 mmHg. What is the volume at 760.0 mmHg

Leviafan [203]

1.7960L

Explanation:

the mass of the gas is constant in both instances

pv/T=constant(according to pv=nRT)

745mmHg*2L/298K=760mmHg*v/273K

v=1.7960L

5 0

3 years ago

A gas mixture contains 3.00 atm of H2 and 1.00 atm of O2 in a 1.00 L vessel at 400K. If the mixture burns to form water while th

sleet_krkn [62]

Answer:

$p_{H_2O}=2.00atm$

Explanation:

Hello!

In this case, according to the following chemical reaction:

$2H_2+O_2\rightarrow 2H_2O$

It means that we need to compute the moles of hydrogen and oxygen that are reacting, via the ideal gas equation as we know the volume, pressure and temperature:

$n_{H_2}=\frac{3.00atm*1.00L}{0.08206\frac{atm*L}{mol*K}*400K}=0.0914molH_2 \\\\n_{O_2}=\frac{1.00atm*1.00L}{0.08206\frac{atm*L}{mol*K}*400K}=0.0305molH_2$

Thus, the yielded moles of water are computed by firstly identifying the limiting reactant:

$n_{H_2O}^{by\ H_2} = 0.0914molH_2*\frac{2molH_2O}{2molH_2} =0.0914molH_2O\\\\n_{H_2O}^{by\ O_2} = 0.0305molO_2*\frac{2molH_2O}{1molO_2} =0.0609molH_2O$

Thus, the fewest moles of water are 0.0609 mol so the limiting reactant is oxygen; in such a way, by using the ideal gas equation once again, we compute the pressure of water:

$p_{H_2O}=\frac{0.0609molH_2O*0.08206\frac{atm*L}{mol*K}*400K}{1.00L}\\\\ p_{H_2O}=2.00atm$

Best regards!

7 0

3 years ago

What is the concentration of an unknown Mg(OH)2 solution if it took an average of 15.4mL of

vova2212 [387]

Answer:

0.077M

Explanation:

Step 1:

The balanced equation for the reaction. This is given below:

2HCl + Mg(OH)2 —> MgCl2 + 2H2O

From the balanced equation above,

The mole ratio of the acid (nA) = 2

The mole ratio of the base (nB) = 1

Step 2:

Data obtained from the question.

Concentration of base Cb =...?

Volume of base (Vb) = 10mL

Concentration of acid (Ca) = 0.1M

Volume of acid (Va) = 15.4mL

Step 3:

Determination of the concentration of the base, Mg(OH)2.

The concentration of the base can be obtained as follow:

CaVa/CbVb = nA/nB

0.1 x 15.4 /Cb x 10 = 2/1

Cross multiply to express in linear form

Cb x 10 x 2 = 0.1 x 15.4

Divide both side by 10 x 2

Cb = (0.1 x 15.4) /(10 x 2)

Cb = 0.077M

Therefore, the concentration of the base, Mg(OH)2 is 0.077M

7 0

3 years ago

Why flame tests are not useful for all elements?

Shalnov [3]

<span>Not all elements have strong visible spectra in a flame</span>

3 0

3 years ago

Read 2 more answers

Identify whether each reaction represents a chemical reaction or a nuclear reaction by filling in the blank with the word ‘chemi

valkas [14]

A chemical reaction is defined as the reaction between two or more substances that produces new substances/compounds.

On the other hand, a nuclear reaction is a reaction that alters the nucleus of a certain atom. This can be done either by splitting the nucleus or by joining this nucleus with another one.

Reaction 1:
Cl₂ + H₂ ............> 2 HCl
This is the combination of two elements to produce a new compound.
Therefore, this reaction is a chemical reaction

Reaction 2:
²₁H + ³₁H .........> ⁴₂H + ¹₀n
This is an alteration in the nucleus of a hydrogen atom by bonding it with another nucleus.
Therefore, this reaction is a nuclear reaction

Hope this helps :)

5 0

3 years ago

Read 2 more answers