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3 years ago

What is true about proportions? Select all that apply.

Chemistry

1 answer:

larisa86 [58]3 years ago

4 0

The true statement about proportions in this context is that; "Proportions have cross products that are equal."

<h2>Proportions in stoichiometry</h2>

The term stoichiometry is umbrella term that encompasses all the calculatrions that are aimed at calculating the amount of substance using mass - volume relationships. Usually, stoichiometry makes use of proportions.

The true statement about proportions in this context is that; "Proportions have cross products that are equal."

Learn more about proportions: brainly.com/question/9743981

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How many liters are present in 10 grams of H2O ?

Luba_88 [7]

Answer:

About 0.01

Explanation:

1 grams of H2O = 0.0010

0.0010 x 10 = 0.01

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3 years ago

Why does it take so much heat and pressure to create helium and other elements?

ehidna [41]

Answer:

To break down the nucleus of an atom

Explanation:

Remember to change from one element to another, is necessary to add protons, neutrons and electrons,in most of the cases.

The take an electron from an atom you need certain energy, but they are in the outside part of the atom so is not as much energy as the one is necessary to take one neutron or proton from the inside part of an atom.

In this way, is a must to have a combination of pressure and heat to destabilize an atom and take some of this subatomic particles.

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3 years ago

The stream table shows the time needed for water to soak into the playfield soil.

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Answer:

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3 years ago

A 1.00 g sample of octane (C8H18) is burned in a bomb calorimeter with a heat capacity of 837J∘C that holds 1200. g of water at

lubasha [3.4K]

Answer:

The heat of combustion for 1.00 mol of octane is -5485.7 kJ/mol

Explanation:

<u>Step 1:</u> Data given

Mass of octane = 1.00 grams

Heat capacity of calorimeter = 837 J/°C

Mass of water = 1200 grams

Temperature of water = 25.0°C

Final temperature : 33.2 °C

<u> Step 2:</u> Calculate heat absorbed by the calorimeter

q = c*ΔT

⇒ with c = the heat capacity of the calorimeter = 837 J/°C

⇒ with ΔT = The change of temperature = T2 - T1 = 33.2 - 25.0 : 8.2 °C

q = 837 * 8.2 = 6863.4 J

<u>Step 3:</u> Calculate heat absorbed by the water

q = m*c*ΔT

⇒ m = the mass of the water = 1200 grams

⇒ c = the specific heat of water = 4.184 J/g°C

⇒ ΔT = The change in temperature = T2 - T1 = 33.2 - 25 = 8.2 °C

q = 1200 * 4.184 * 8.2 = 41170.56 J

<u>Step 4</u>: Calculate the total heat

qcalorimeter + qwater = 6863.4 + 41170. 56 = 48033.96 J = 48 kJ

Since this is an exothermic reaction, there is heat released. q is positive but ΔH is negative.

<u>Step 5</u>: Calculate moles of octane

Moles octane = 1.00 gram / 114.23 g/mol

Moles octane = 0.00875 moles

<u>Step 6:</u> Calculate heat combustion for 1.00 mol of octane

ΔH = -48 kJ / 0.00875 moles

ΔH = -5485.7 kJ/mol

The heat of combustion for 1.00 mol of octane is -5485.7 kJ/mol

8 0

3 years ago

The molar heat of fusion of gold is 12.550 kJ mol–1. At its melting point, how much mass of melted gold must solidify to release

KATRIN_1 [288]

The mass of melted gold to release the energy would be 3, 688. 8 Kg

<h3>How to determine the mass</h3>

The formula for quantity of energy is given thus;

Q = n × HF

Where n represents number of moles

HF represents heat of fusion

To find the number of moles, we have

235.0 = n × 12.550

number of moles = $\frac{235}{12. 550}$ = 18. 725 moles

Note that molar mass of Gold is 197g/ mol

Let's note that;

Number of moles = mass/ molar mass

Mass = number of moles × molar mass

Mass = 18. 725 × 197

Mass = 3, 688. 8 Kg

Thus, the mass of melted gold to release the energy would be 3, 688. 8 Kg

Learn more about molar heat of fusion here:

brainly.com/question/15634085

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2 years ago