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2 years ago

¿Quién estableció el concepto moderno de elemento?

Chemistry

1 answer:

Zina [86]2 years ago

7 0

Answer:

Robert Boyle

Explanation:

En muchos textos se suele considerar a Robert Boyle como el científico que introdujo en la Química un concepto de elemento diferente al empleado por los aristotélicos o por los alquimistas y que sirvió de antecedente al que formulara Lavoisier en 1789.

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If i add water to 100 mL of a 0.15M NaOH solution until the final volume 150mL , what will the molarity of the diluted solution

labwork [276]

0,15 moles of NaOH-------in------------1000ml
x moles of NaOH------------in--------100ml
x = 0,015 moles of NaOH

final volume = 150ml

0,015 moles of NaOH---in-------150ml
x moles of NaOH--------------in-----1000ml
x = 0,1 moles of NaOH

answer: 0,1mol/dm³ (molarity)

3 0

3 years ago

Chicago is about 2,800 km from Los Angeles. About how long would it take a jet plane flying 800 km/h to fly from Chicago to Los

BaLLatris [955]

<u>Answer:</u> The time taken by jet plane to reach Los Angeles from Chicago is 3.5 hours

<u>Explanation:</u>

Speed is defined as the rate at which an object moves with respect to time.

To calculate the time taken for the given speed, we use the equation:

$s=\frac{d}{t}$

where,

s = speed of the jet plane = 800 km/hr

d = distance traveled = 2800 km

t = time taken by jet plane = ?

Putting values in above equation, we get:

$800km/hr=\frac{2800km}{t}\\\\t=\frac{2800km}{800km/hr}=3.5hr$

Hence, the time taken by jet plane to reach Los Angeles from Chicago is 3.5 hours

4 0

3 years ago

A certain drug has a half-life in the body of 3.5h. Suppose a patient takes one 200.Mg pill at :500PM and another identical pill

tekilochka [14]

Answer:

The amount of drug left in his body at 7:00 pm is 315.7 mg.

Explanation:

First, we need to find the amount of drug in the body at 90 min by using the exponential decay equation:

$N_{t} = N_{0}e^{-\lambda t}$

Where:

λ: is the decay constant = $ln(2)/t_{1/2}$

$t_{1/2}$ : is the half-life of the drug = 3.5 h

N(t): is the quantity of the drug at time t

N₀: is the initial quantity

After 90 min and before he takes the other 200 mg pill, we have:

$N_{t} = 200e^{-\frac{ln(2)}{3.5 h}*90 min*\frac{1 h}{60 min}} = 148.6 mg$

Now, at 7:00 pm we have:

$t = 7:00 pm - (5:00 pm + 90 min) = 30 min$

$N_{t} = (200 + 148.6)e^{-\frac{ln(2)}{3.5 h}*30 min*\frac{1 h}{60 min}} = 315.7 mg$

Therefore, the amount of drug left in his body at 7:00 pm is 315.7 mg (from an initial amount of 400 mg).

I hope it helps you!

3 0

2 years ago

Which statements describe Earth's continents? Check all that apply.

kari74 [83]

Answer:

A continent is a large distinct landmass.

There are seven continents on Earth.

Continents cover two-thirds of Earth’s surface.

Explanation:

8 0

2 years ago

You could add solid KCl to the solution to precipitate out AgCl(s). What mass of KCl is needed to precipitate the silver ions fr

padilas [110]

Answer:

0.143 g of KCl.

Explanation:

Equation of the reaction:

AgNO3(aq) + KCl(aq) --> AgCl(s) + KNO3(aq)

Molar concentration = mass/volume

= 0.16 * 0.012

= 0.00192 mol AgNO3.

By stoichiometry, 1 mole of AgNO3 reacts with 1 mole of KCl to form a precipitate.

Number of moles of KCl = 0.00192 mol.

Molar mass of KCl = 39 + 35.5

= 74.5 g/mol

Mass = molar mass * number of moles

= 74.5 * 0.00192

= 0.143 g of KCl.

4 0

3 years ago