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4 years ago

Based on your knowledge of energy conservation, which of the following statements is true?

1 answer:

3 0

C. both a and b

If a light bulb can last longer with the same amount of energy it is given, that means it can use less energy to do the same job compared to one that does not last longer with the same amount of energy it is given. It is much like how a more fuel efficient car will be able to go farther on the same tank of gas, but if you pair it with a car that doesn't have as great of an mpg, when they go the same distance, the car with the greater mpg spends less fuel.

If you don't have to use the energy when you aren't utilizing it, then you can conserve the energy for when you do need it.

You might be interested in

If you had an aqueous mixture that contained Ag+ , K+ , and Pb2+ cations, how many different solids could precipitate if a chlor

SCORPION-xisa [38]

Answer:

Two, KCl and PbCl₂.

Explanation:

Hello!

In this case, since the addition of chloride ions promote the following three ionic reactions:

$Ag^+(aq)+Cl^-(aq)\rightleftharpoons AgCl(s)\\\\K^+(aq)+Cl^-(aq)\rightleftharpoons KCl(aq)\\\\Pb^{2+}(aq)+Cl^-(aq)\rightleftharpoons PbCl_2(s)$

We can infer that both silver chloride and lead (II) chloride are precipitated products as their Ksp are 6.56x10⁻⁴ and 1.59x10⁻⁵ respectively, which means they are merely soluble in water.

Best regards!

3 0

3 years ago

Why do chemical equations need to be balanced?

velikii [3]

Because if they are not balanced, then the amount of reaction is not equal to the amount of the product. You must have the same ratio of atoms on both sides of the equation because we are not losing moles of each element.

7 0

3 years ago

P is the pressure in atmospheres (atm), V is the volume in liters (L), n is the number of moles, R is the gas constant (0.0821 L

yKpoI14uk [10]

Answer:

The mass of the neon gas m = 1.214 kg

Explanation:

Pressure = 3 atm = 304 k pa

Volume = 0.57 L = 0.00057 $m^{3}$

Temperature = 75 °c = 348 K

Universal gas constant = 0.0821 $\frac{L . atm}{mol K}$

We have to change the unit of this constant. it may be written as

Universal gas constant = 8.314 $\frac{KJ}{mol K}$

Gas constant for neon = $\frac{8.314}{20}$ = 0.41 $\frac{KJ}{kg K}$

From ideal gas equation,

P V = m R T ------- (1)

We have all the variables except m. so we have to solve this equation for mass (m).

⇒ 304 × $10^{3}$ × 0.00057 = m × 0.41 × 348

⇒ 173.28 = 142.68 × m

⇒ m = 1.214 kg

This is the mass of the neon gas.

4 0

3 years ago

Given the chemical equation: Fe2O3 + 3CO --> 2Fe + 3CO2

lapo4ka [179]

Answer:

The answer to your question is 160 g of Fe₂O₃

Explanation:

Data

mass of Fe = 112 g

mass of CO = in excess

mass of Fe₂O₃ = ?

Balanced chemical reaction

Fe₂O₃ + 3CO ⇒ 2Fe + 3CO₂

Process

1.- Calculate the molar mass of Fe₂O₃ and Fe

Molar mass Fe₂O₃ = (56 x 2) + (16 x 3) = 112 + 48 = 160 g

atomic mass of Fe = 56

2.- Use proportions to calculate the mass of Fe₂O₃ needed

160 g of Fe₂O₃ ------------------- 2(56) g of Fe

x g of Fe₂O₃ ------------------ 112 g of Fe

x = (112 x 160) / 2(56)

x = 17920/112

x = 160 g of Fe₂O₃

6 0

3 years ago

1. Which of the following is a correctly written thermochemical equation?

WITCHER [35]

Explanation:

1. Thermochemical equation is balance stoichiometric chemical equation written with the phases of the reactants and products in the brackets along with the enthalpy change of the reaction.

The given correct thermochemical reactions are:

$Fe(s)+O_2(g)\rightarrow Fe_2O_3(s),\Delta H = 3,926 kJ
$

$C_3H_8(g)+5O_2 (g)\rightarrow 3CO_2 (g)+4H_2O(l),\Delta H= 2,220 kJ/mol$

2. Phase change affect the value of the enthalpy change of the thermochemical equation. This is because change in phase is accompanied by change in energy. For example:

$H_2O(s)\rightarrow H_2O(g),\Delta H_{s}=51.1 kJ/mol$

$H_2O(l)\rightarrow H_2O(g),\Delta H_{v}=40.65 kJ/mol$

In both reaction phase of water is changing with change in energy of enthalpy of reaction.

7 0

3 years ago

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