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ira [324]
3 years ago
15

Circle the letter of each expression that has four significant figures. a. 1.25 104 b. 12.51

Chemistry
1 answer:
DiKsa [7]3 years ago
4 0

B is the answer

1 2 5 1

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How long it takes a 100 watt light bulb to use 10,000 J of electrical energy?​
vlabodo [156]

Answer:

A 100-watt light bulb takes 100 seconds to use 10,000 J of electrical energy.

Explanation:

Power refers to the amount of work done (or energy consumed) per unit of time. It is usually measured in watts (W), which is equal to 1 Joules per second (\frac{J}{s})

So, by definition, to calculate the power consumed or supplied in a time interval the following expression is used:

P=\frac{W}{t}

where P is the power measured in Watts, W is the work measured in Joules, and t is the time measured in seconds.

In this case:

  • P=100 Watt
  • W= 10,000 J
  • t= ?

Replacing:

100 Watt=\frac{10,000 J}{t}

Solving:

t=\frac{10,000 J}{100 Watt}

t=100 seconds

<u><em> A 100-watt light bulb takes 100 seconds to use 10,000 J of electrical energy.</em></u>

<u><em></em></u>

7 0
3 years ago
Using the table below, what is the change in enthalpy for the following reaction? 3CO (g) + 2Fe2O3 (s) Imported Asset Fe(s) + 3C
zhuklara [117]

To solve this problem, we should recall that the change in enthalpy is calculated by subtracting the total enthalpy of the reactants from the total enthalpy of the products:

ΔH = Total H of products – Total H of reactants

You did not insert the table in this problem, therefore I will find other sources to find for the enthalpies of each compound.

ΔHf CO2 (g) = -393.5 kJ/mol

ΔHf CO (g) = -110.5 kJ/mol

ΔHf Fe2O3 (s) = -822.1 kJ/mol

ΔHf Fe(s) = 0.0 kJ/mol

Since the given enthalpies are still in kJ/mol, we have to multiply that with the number of moles in the formula. Therefore solving for ΔH:

ΔH = [<span>3 mol </span><span>( − </span><span>393.5 </span>kJ/mol<span>) + 1 mol (</span>0.0 kJ/mol)<span>] − [</span><span>3 mol </span><span>( − </span><span>110.5 </span>kJ/mol<span>) + </span><span>2 mol </span><span>( − </span><span>822.1 </span>kJ/mol<span>)]</span>

ΔH = <span>795.2 kJ</span>

3 0
3 years ago
HOW DO YOU GET ANY THING YOU WANT PLS
r-ruslan [8.4K]

Answer:

enough money can buy you anything

6 0
3 years ago
Read 2 more answers
Gaseous hydrogen iodide is placed in a closed container at 425∘C, where it partially decomposes to hydrogen and iodine: 2HI(g)⇌H
murzikaleks [220]

Answer:

0.0184

Explanation:

Let's consider the following reaction at equilibrium.

2 HI(g) ⇌ H₂(g) + I₂(g)

The concentration equilibrium constant (Kc) is equal to the product of the concentration of the products raised to their  stoichiometric coefficients divided by the product of the concentration of the reactants raised to their  stoichiometric coefficients.

Kc = [H₂] × [I₂] / [HI]²

Kc = (4.78 × 10⁻⁴) × (4.78 × 10⁻⁴) / (3.52 × 10⁻³)²

Kc = 0.0184

5 0
3 years ago
Why does a raindrop accelerate as it falls to the earth?
allochka39001 [22]
Acceleration is the rate at which an object changes its speed. When a raindrop is falling down from the clouds due to gravity, the veloicty is pretty much fast, however air resistance comes in action and slows the droplet down... it gives it a constant speed until it hits the ground

6 0
3 years ago
Read 2 more answers
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