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3 years ago

Plzzz fastttt answerrr

Chemistry

1 answer:

Lady_Fox [76]3 years ago

5 0

Answer:

Communication between scientists increased.

Technological advancements were made.

Explanation:

The options:

Metalworkers began using new metals.

Communication between scientists increased.

The American Civil War started.

Technological advancements were made.

The reasons the number of known elements more than double by 1861 would be because technological advancements have been made and communication between scientists increased.

With the advancement in technology, more equipment become available and research became more sophisticated leading to new discoveries. The new discoveries would not have made much difference if they are not adequately communicated to other scientists.

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A 50.6 grams sample of magnesium hydroxide (Mg(OH)2) is reacted with 45.0 grams of hydrochloric acid (HCl). What is the theoreti

zysi [14]

Mg(OH)2(s) + 2HCl(aq) yield MgCl2(aq) + 2H2O(l)

grams HCl required = (50.6 grams Mg(OH)2) * (1 mol Mg(OH)2 / 58.3197 grams Mg(OH)2) * (2 mol HCl / 1 mol Mg(OH)2) * (36.453 grams HCl / 1 mol HCl) = 63.26 grams HCl required

Since there are only 45.0 grams HCl, then HCl is the limiting reactant.

theoretical yield MgCl2 = (45.0 grams HCl) * (1 mol HCl / 36.453 grams HCl) * (1 mol MgCl2 / 2 mol HCl) * (95.211 grams MgCl2 / 1 mol MgCl2) = 58.6 grams MgCl2

7 0

3 years ago

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A gas sample with a volume of 1,500 cm® is heated from -65 °C to 75 °C. Assuming the

djverab [1.8K]

Answer:

V₂ = 2509.62 cm³

Explanation:

Given data:

Initial volume = 1500 cm³

Initial temperature = -65°C (-65 + 273 = 208 K)

Final temperature = 75°C ( 75 +273 = 348 K)

Final volume = ?

Solution:

The given problem will be solve through the Charles Law.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume

T₂ = Final temperature

Now we will put the values in formula.

V₁/T₁ = V₂/T₂

V₂ = V₁T₂/T₁

V₂ = 1500 cm³ × 348 K / 208 k

V₂ = 522000 cm³.K / 208 k

V₂ = 2509.62 cm³

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3 years ago

Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid-fuel ro

melamori03 [73]

Answer: The mass of nickel (II) oxide and aluminium that must be used is 18.8 g and 4.54 g respectively.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For nickel:

Given mass of nickel = 14.8 g

Molar mass of nickel = 58.7 g/mol

Putting values in equation 1, we get:

$\text{Moles of nickel}=\frac{14.8g}{58.7g/mol}=0.252mol$

For the given chemical reaction:

$3NiO(s)+2Al(s)\rightarrow 3Ni(l)+Al_2O_3(s)$

For nickel (II) oxide:

By Stoichiometry of the reaction:

3 moles of nickel are produced from 3 moles of nickel (II) oxide

So, 0.252 moles of nickel will be produced from $\frac{3}{3}\times 0.252=0.252mol$ of nickel (II) oxide

Now, calculating the mass of nickel (II) oxide by using equation 1:

Molar mass of nickel (II) oxide = 74.7 g/mol

Moles of nickel (II) oxide = 0.252 moles

Putting values in equation 1, we get:

$0.252mol=\frac{\text{Mass of nickel (II) oxide}}{74.7g/mol}\\\\\text{Mass of nickel (II) oxide}=(0.252mol\times 74.7g/mol)=18.8g$

For aluminium:

By Stoichiometry of the reaction:

3 moles of nickel are produced from 2 moles of aluminium

So, 0.252 moles of nickel will be produced from $\frac{2}{3}\times 0.252=0.168mol$ of aluminium

Now, calculating the mass of aluminium by using equation 1:

Molar mass of aluminium = 27 g/mol

Moles of aluminium = 0.168 moles

Putting values in equation 1, we get:

$0.168mol=\frac{\text{Mass of aluminium}}{27g/mol}\\\\\text{Mass of aluminium}=(0.168mol\times 27g/mol)=4.54g$

Hence, the mass of nickel (II) oxide and aluminium that must be used is 18.8 g and 4.54 g respectively.

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An earthquake's magnitude is a measure of how much energy an earthquake releases. Typically, the richter scale is used.

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3 years ago

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777dan777 [17]

ELETRICK probably wondering why metal shocks (psst why does wires charge phones)

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