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3 years ago

What is the atomic number of an element that has seven protons and eight neutrons and seven electrons?

Chemistry

2 answers:

Dmitrij [34]3 years ago

7 0

Answer:

Nitrogen has an atomic number of 7 (Z=7) because it has 7 protons in its nucleus. Some nitrogen atoms have an atomic mass number of 15 (A=15). A is the number of neutrons plus protons in the nucleus. However, we already know that there are 7 protons

Darya [45]3 years ago

6 0

Answer:

Atomic number = Number of protons = Number of electrons

Atomic number = 7

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How many grams of carbon monoxide are needed to react with an excess of iron (III) oxide to produce 198.5 grams of iron? Fe2O3(s

erastova [34]

Answer : The grams of carbon monoxide needed are 148.89 g

Solution : Given,

Mass of iron, Fe = 198.5 g

Molar mass of iron, Fe = 56 g/mole

Molar mass of carbon monoxide, CO = 28 g/mole

First we have to calculate the moles of iron, Fe.

$\text{ Moles of Fe}=\frac{\text{ Mass of Fe}}{\text{ Molar mass of Fe}}=\frac{198.5g}{56g/mole}=3.545moles$

The balanced chemical reaction is,

$Fe_2O_3(s)+3CO(g)\rightarrow 3CO_2(g)+2Fe(s)$

From the balanced reaction, we conclude that

2 moles of iron produces from the 3 moles of carbon monoxide

3.545 moles of iron produces from the $\frac{3}{2}\times 3.545=5.3175$ moles of carbon monoxide

Now we have to calculate the mass of carbon monoxide, CO.

$\text{ Mass of CO}=\text{ Moles of CO}\times \text{ Molar mass of CO}$

$\text{ Mass of CO}=(5.3175moles)\times (28g/mole)=148.89g$

Therefore, the grams of carbon monoxide needed are 148.89 g

7 0

3 years ago

A concentration cell is constructed by using the same half-reaction for both the cathode and anode. What is the value of standar

Akimi4 [234]

Solution :

A cell that is concentrated is constructed by the same half reaction for the anode as well as he cathode.

We know,

In a standard cell,

the reduction half cell reaction is :

$Ag^+(aq)+e^- \rightarrow Ag(s) E^0 = -0.80 \ V$

The oxidation half ell reaction :

$Ag(s) \rightarrow Ag^+(aq) + e^- \ E^0= +0.80 \ V$

Thus the complete reaction of the cell is :

$Ag^+(aq)+ Ag(s) \rightarrow Ag^+(aq)+Ag(s)$

$E^0$ cell = $E_R - E_L = 0.00 \ \text{volts}$

7 0

2 years ago

You drop a rock weighing 23.2 g into a graduated cylinder that contains 55 mL. The level of the water rises to 62 mL. What is th

ra1l [238]

The density of the rock is 3.314g/mL

CALCULATE DENSITY:

According to this question, a rock weighs 23.2g. After dropping the rock into a graduated cylinder containing 55mL of water, the level changes to 62mL.

This means that the volume of the rock can be calculated as follows:

Volume of rock = 62mL - 55mL

Volume of rock = 7mL

Density can be calculated using the formula as follows:

Density = mass ÷ volume

Density = 23.2 ÷ 7

Density = 3.314g/mL

Therefore, the density of the rock is 3.314g/mL

Learn more: brainly.com/question/6034174?referrer=searchResults

4 0

3 years ago

A science student wants to use distillation to separate a mixture of two

statuscvo [17]

Answer:

Boiling point

Explanation:

Distillation is one of the most widely used separation technique in chemistry. It is used to separate a mixture of liquid substances with different boiling point. Hence, the basis of the separation is BOILING POINT DIFFERENCE.

In the procedure, the liquid substances are heated until they turn gaseous, which they do at different times considering their different boiling points. The separated components are then converted back to liquid states in a process called CONDENSATION.

6 0

3 years ago

¿Cómo se escribe la fórmula molecular (orden de los iones)?

cluponka [151]

Answer:

A la izquierda el catión y a la derecha el anión.

Explanation:

¡Hola!

En este caso, y basado en las normas IUPAC para la escritura de las fórmulas moleculares, es necesario primero escribir el catión a la izquerda, seguido del anión a la derecha, tal y como se muestra en los siguientes ejemplos, recordando que el catión es el ion cargado positivamente y el anión, negativamente:

$K^+Cl^-\\\\Ag_2^+(SO_4)^{2-}$

Los cuales son cloruro de potasio y sulfato de plata respectivamente. También es necesario tener en cuenta que los metales tienden a ser cationes por su capacidad de perder electrones, mientras que los no metales a ganarlos y por ende resultar como aniones.

¡Un gusto ayudarte!

6 0

3 years ago