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3 years ago

Which is a FALSE statement about elements?

Chemistry

2 answers:

svetlana [45]3 years ago

6 0

C. Not each element has a known neutron number

OlgaM077 [116]3 years ago

3 0

Answer:

Option c, Each element has its own neutron number

Explanation:

Atomic number of any element is unique. All the atoms of an element have the same atomic number. Atomic number defines the identity of the element.

Atomic number is equal to number of proton. So, number of proton is also unique or each element has its own number of proton.

Chemical symbols are used to represent element in easiest way. Therefore, chemical symbol has to be specific for each element.

Atoms of an element can have different number of neutrons. Atoms of an element having same no. of proton but different no. of neutron are called isotopes.

So, among the given option, option c is false.

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Be sure to answer all parts. The percent by mass of bicarbonate (HCO3−) in a certain Alka-Seltzer product is 32.5 percent. Calcu

pochemuha

Answer : The volume of $CO_2$ will be, 514.11 ml

Explanation :

The balanced chemical reaction will be,

$HCO_3^-+HCl\rightarrow Cl^-+H_2O+CO_2$

First we have to calculate the mass of $HCO_3^-$ in tablet.

$\text{Mass of }HCO_3^-\text{ in tablet}=32.5\% \times 3.79g=\frac{32.5}{100}\times 3.79g=1.23175g$

Now we have to calculate the moles of $HCO_3^-$ .

Molar mass of $HCO_3^-$ = 1 + 12 + 3(16) = 61 g/mole

$\text{Moles of }HCO_3^-=\frac{\text{Mass of }HCO_3^-}{\text{Molar mass of }HCO_3^-}=\frac{1.23175g}{61g/mole}=0.0202moles$

Now we have to calculate the moles of $CO_2$ .

From the balanced chemical reaction, we conclude that

As, 1 mole of $HCO_3^-$ react to give 1 mole of $CO_2$

So, 0.0202 mole of $HCO_3^-$ react to give 0.0202 mole of $CO_2$

The moles of $CO_2$ = 0.0202 mole

Now we have to calculate the volume of $CO_2$ by using ideal gas equation.

$PV=nRT$

where,

P = pressure of gas = 1.00 atm

V = volume of gas = ?

T = temperature of gas = $37^oC=273+37=310K$

n = number of moles of gas = 0.0202 mole

R = gas constant = 0.0821 L.atm/mole.K

Now put all the given values in the ideal gas equation, we get :

$(1.00atm)\times V=0.0202 mole\times (0.0821L.atm/mole.K)\times (310K)$

$V=0.51411L=514.11ml$

Therefore, the volume of $CO_2$ will be, 514.11 ml

6 0

3 years ago

Match the vocabulary with the definitions.

Fiesta28 [93]

1: Decomposition reaction
2: Combination reaction
3: product
4: Reactant

8 0

3 years ago

Which of the following best describes how soil is formed?

harkovskaia [24]

Answer:

Soil minerals form the basis of soil.

Explanation:

They are produced from rocks (parent material) through the processes of weathering and natural erosion. Water, wind, temperature change, gravity, chemical interaction, living organisms and pressure differences all help break down parent material.

5 0

3 years ago

A chemical bond is a strong attraction between two or more atoms. Can you identify the properties of different types of chemical

kakasveta [241]

Answer:

1. Ionic bond.

2.Ions

3. Covalent

4.Single bond

5. Double bond

6. Polar bond

7.Non polar bond

8. Hydrogen bond

5 0

3 years ago

Read 2 more answers

Classify each process as either physical or a chemical change.

Dafna11 [192]

Answer:

I think they are all correct

7 0

3 years ago