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3 years ago

When Mendeleev organized the elements by their _________, he noticed the properties of elements repeated.

Chemistry

1 answer:

Mama L [17]3 years ago

4 0

I believe it should be when he arranged the elements by their atomic mass.

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If the pressure is 0.9 kPa. and the volume is 4.0L, then the pressure changes to 0.20 kPa. What is the new volume?

ch4aika [34]

Answer:

18 L

Explanation:

boyles law

P1V1 = P2V2

V2 = P1V1/P2

V2 = (.9 * 4)/.2

V2 = 18

4 0

2 years ago

What is the density of a substance that has a mass of 20 g and a volume of<br> 10 mL?

Paha777 [63]

Answer:

That unknown substance is water

Explanation:

3 0

2 years ago

10. A 2.36-gram sample of NaHCO3 was completely decomposed in an

Airida [17]

Answer:

0.79 g

Explanation:

Let's introduce a strategy needed to solve any similar problem like this:

Apply the mass conservation law (assuming that this reaction goes 100 % to completion): the total mass of the reactants should be equal to the total mass of the products.

Based on the mass conservation law, we need to identify the reactants first. Our only reactant is sodium bicarbonate, so the total mass of the reactants is:

$m_r=m_{NaHCO_3}=2.36 g$

We have two products formed, sodium carbonate and carbonic acid. This implies that the total mass of the products is:

$m_p=m_{Na_2CO_3}+m_{H_2CO_3}$

Apply the law of mass conservation:

$m_r=m_p$

Substitute the given variables:

$m_{NaHCO_3}=m_{Na_2CO_3}+m_{H_2CO_3}$

Rearrange for the mass of carbonic acid:

$m_{H_2CO_3}=m_{NaHCO_3}-m_{Na_2CO_3}=2.36 g - 1.57 g=0.79 g$

8 0

3 years ago

The force against a solid object moving through a gas or a liquid

statuscvo [17]

A force or a type of friction?

Force: Resistance--> If you go swimming, you feel the water pushing against you, making it harder to walk in water and even to swim unless you are doggy pattling or front strokes. Resistance is a force going against a solid object.

Friction: Fluid friction which is friction that occurs after a solid object travels through a liquid or gas

5 0

3 years ago

Using the periodic table, determine which material is most likely to be a good conductor. A. sodium B. bromine C. carbon D. oxyg

grandymaker [24]

A. Because sodium is a metal and metals are good conductors

7 0

2 years ago