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2 years ago

Which of the following is a balanced equation?Select one:a. Ab. Bc. Cd. D

Chemistry

1 answer:

Phantasy [73]2 years ago

3 0

Answer:

Explanation:

Balanced equations have the same number of elements on both sides. If the number of elements are equal to each other for every element in the equation on both sides, then the equation is balanced.

Important concept : The big number before an element or compound represents how many molecules of that compound or element there are in a reaction. To find the number of atoms of each element you multiply the coefficient by the subscript ( small number ) which represents the number of atoms of that element in each molecule. Ex. 3H2O. There is a coefficient of 3 meaning that there are 3 molecules of H2O. There is a subscript after H meaning there are 2 atoms of hydrogen in each molecule. To find the total number of atoms we multiply the subscript of hydrogen by the coefficient of the whole molecule. 3 * 2 = 6 , so there are a total of 6 atoms of hydrogen in 3H2O

A) Cu + 2AgNO3 ==> CuNO3 + 2Ag

1 Cu 1

2 Ag 2

2 N 1

3 O 3

The amount of nitrogen atoms is different on both sides of the equation therefore this is not a balanced equation

B) CCl4 + O2 ==> CO2 + 2Cl2

1 C 1

4 Cl 4

2 O 2

The number of atoms of each element is the same on both sides of the equation therefore this is the balanced equation, however lets check the other answer choices just in case.

C) 2K + H2SO4 ==> K2SO4 + 2H2

2 K 2

1 H 4

1 S 1

4 O 4

The number of Hydrogen atoms are different on each side of the equation therefore this is not a balanced equation.

D) 2Al2O3 ==> 2Al + 3O2

4 Al 2

6 O 6
There are a different amount of aluminum atoms on both sides of the equation therefore this is not a balanced equation.

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1.20 x 10^22 molecules NaOH to gram

Trava [24]

Answer:

$\boxed {\boxed {\sf 0.797 \ g \ NaOH}}$

Explanation:

<u>1. Convert Molecules to Moles</u>

First, we must convert molecules to moles using Avogadro's Number: 6.022*10²³. This tells us the number of particles in 1 mole of a substance. In this case, the particles are molecules of sodium hydroxide.

$\frac {6.022*10^{23} \ molecules \ NaOH} {1 \ mol \ NaOH}}$

Multiply by the given number of molecules.

$1.20*10^{22} \ molecules \ NaOH *\frac {6.022*10^{23} \ molecules \ NaOH} {1 \ mol \ NaOH}}$

Flip the fraction so the molecules cancel out.

$1.20*10^{22} \ molecules \ NaOH *\frac {1 \ mol \ NaOH} {6.022*10^{23} \ molecules \ NaOH}}$

$1.20*10^{22} *\frac {1 \ mol \ NaOH} {6.022*10^{23}}}$

$\frac {1.20*10^{22} \ mol \ NaOH} {6.022*10^{23}}}$

$0.0199269345732 \ mol \ NaOH$

<u>2. Convert Moles to Grams</u>

Next, we convert moles to grams using the molar mass.

We must calculate the molar mass using the values on the Periodic Table. Look up each individual element.

Na: 22.9897693 g/mol
O: 15.999 g/mol
H: 1.008 g/mol

Since the formula has no subscripts, we can simply add the molar masses.

NaOH: 22.9897693+15.999+1.008=39.9967693 g/mol

Use this as a ratio.

$\frac {39.9967693 \ g \ NaOH }{1 \ mol \ NaOH}$

Multiply by the number of moles we calculated.

$0.0199269345732 \ mol \ NaOH*\frac {39.9967693 \ g \ NaOH }{1 \ mol \ NaOH}$

The moles of sodium hydroxide cancel.

$0.0199269345732 *\frac {39.9967693 \ g \ NaOH }{1}$

$0.0199269345732 *39.9967693 \ g \ NaOH$

$0.79701300498 \ g \ NaOH$

The original measurement of molecules has 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place. The 0 tells us to leave the 7 in the hundredth place.

$0.797 \ g \ NaOH$

1.20*10²² molecules of sodium hydroxide is approximately 0.797 grams.

4 0

2 years ago

Consider 5.00 L of a gas at 365 mmHg and 20. ∘C . If the container is compressed to 2.30 L and the temperature is increased to 4

lakkis [162]

Answer:

P₂ = 1.12 atm

Explanation:

To find the new pressure, you need to use the Combined Gas Law:

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

In this equation, "P₁", "V₁", and "T₁" represent the initial pressure, volume, and temperature. "P₂", "V₂", and "T₂" represent the new pressure, volume, and temperature. Before plugging the values into the equation, you need to

(1) convert the pressure from mmHg to atm (760 mmHg = 1 atm)

(2) convert the temperatures from Celsius to Kelvin (°C + 273)

The final answer should have 3 sig figs like the given values.

P₁ = 365 mmHg / 760 = 0.480 atm P₂ = ? atm

V₁ = 5.00 L V₂ = 2.30 L

T₁ = 20°C + 273 = 293 K T₂ = 40°C + 273 = 313 K

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$ <----- Combined Gas Law

$\frac{(0.480 atm)(5.00 L)}{293 K}=\frac{P_2(2.30 L)}{313 K}$ <----- Insert values