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3 years ago

Each element is defined by the number of

Chemistry

2 answers:

Nastasia [14]3 years ago

6 0

Each number is defined by the number of protons.

pentagon [3]3 years ago

4 0

Answer:

The atomic number of an element is equal to the number of protons in each atom and defines the element. For example, all carbon atoms contain 6 protons in their atomic nucleus; so the atomic number of carbon is 6.

What does the number of an element represent?

The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus of every atom of that element. The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus.

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To determine the mass of CO2 that forms from a given mass of CaCO3, which of the following must be known? Check all that apply.

ZanzabumX [31]

To determine the mass of CO₂, the following must be known :

the molar mass of CaCO₃
the mole ratio of CaCO₃ to CO₂
the molar mass of CO₂

<h3>Further explanation</h3>

Reaction

Decomposition of CaCO₃

CaCO₃ ⇒ CaO + CO₂

Given the mass of CaCO₃, so to determine the mass of CO₂ :

1. Find the mol of CaCO₃ from the molar mass of CaCO₃

$\tt n_{CaCO_3}=\dfrac{mass~CaCO_3}{MW~CaCO_3}$

2. Find the mole ratio of CaCO₃ : CO₂(from equation = 1 : 1)

$\tt n_{CaCO_3}\div n_{CO_2}=1\div 1$

3. Find the mass of CO₂ from the molar mass of CO₂

$\tt mass_{CO_2}=n_{CO_2}\times MW_{CO_2}$

3 0

3 years ago

Read 2 more answers

PLZZZZ HELP Me plzzz

STALIN [3.7K]

I believe the third one if i am not mistaken

3 0

3 years ago

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What would be the composition and ph of an ideal buffer prepared from lactic acid (ch3chohco2h), where the hydrogen atom highlig

Mashutka [201]

Answer:

$P_H =2.86$

$c=1.4\times 10^{-4}$

Explanation:

first write the equilibrium equaion ,

$C_3H_6O_3$ ⇄ $C_3H_5O_3^{-} +H^{+}$

assuming degree of dissociation $\alpha$ =1/10;

and initial concentraion of $C_3H_6O_3$ =c;

At equlibrium ;

concentration of $C_3H_6O_3 = c-c\alpha$

$[C_3H_5O_3^{-} ]= c\alpha$

$[H^{+}] = c\alpha$

$K_a = \frac{c\alpha \times c\alpha}{c-c\alpha}$

$\alpha$ is very small so $1-\alpha$ can be neglected

and equation is;

$K_a = {c\alpha \times \alpha}$

$[H^{+}] = c\alpha$ = $\frac{K_a}{\alpha}$

$P_H =- log[H^{+} ]$

$P_H =-logK_a + log\alpha$

$K_a =1.38\times10^{-4}$

$\alpha = \frac{1}{10}$

$P_H= 3.86-1$

$P_H =2.86$

composiion ;

$c=\frac{1}{\alpha} \times [H^{+}]$

$[H^{+}] =antilog(-P_H)$

$[H^{+} ] =0.0014$

$c=0.0014\times \frac{1}{10}$

$c=1.4\times 10^{-4}$

6 0

4 years ago

What is a sentence using composition.<br>

klemol [59]

Answer:

Son aquellas en las que hay más de un verbo núcleo de predicado, por lo que dos o más oraciones forman una más grande; por ejemplo: A Carlos le gusta el fútbol, pero a María solo le gusta el cricket.

Explanation:

7 0

3 years ago

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Flammabilty. Is a chemical property that tells whether a substance reacts in the presence of carbon dioxide try or false

beks73 [17]

Answer:

False

Explanation:

Flammability is a chemical property that tells whether a substance reacts in the presence of extreme heat, spark, or another form of ignition.

4 0

3 years ago