All categories

3 years ago

how was it possible that Mendeleev was able to predict the properties of elements that no one knew about

1 answer:

7 0

<span>He used the patterns he found in properties of known elements to predict the properties of unknown elements.</span>

You might be interested in

I don't know how to do any of these.plz help.its a study guide for my chemistry exam tomorrow ✌

Vladimir [108]

6.02 x 1023 atoms weigh out 63.55 grams copper.

No. of Molecules in water = 3.5mole x (6.02 x 10^23) molecules/mole = 2.107 x 10^24 molecules of H2O

8 0

3 years ago

A children's liquid medicine contains 100mg of active ingredient in 5 mL. If a child should receive 200 mg of the active ingredi

GaryK [48]

Answer: 10ml
In this question, you are given the liquid medicine concentration (100mg/5ml) and the doses of the medicine that must be taken(200mg). You are asked how much ml of the drug needed. Then the calculation would be:

Volume of drug needed= doses of the drug / drug concentration
Volume of drug needed= 200mg / (100mg/5ml)= 10ml

8 0

3 years ago

C2H4O2 + NaC2H3O2 + H2O + CO2 list the reactants in this chemical reaction

lisabon 2012 [21]

Answer:

C₂H₄O₂ and NaC₂H₃O₂ are reactants.

Explanation:

Word equation:

Acetic acid + sodium acetate → sodium diacetate

Chemical equation:

C₂H₄O₂ + NaC₂H₃O₂ → C₄H₇NaO₄

This is a synthesis reaction in which simple reactants combine to form complex product.

This is also balanced chemical equation because there are equal number of atoms of all elements on both side of equation. Thus it follow the law of conservation of mass.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

This law was given by french chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

7 0

3 years ago

What factors do you think should be considered in selecting a metal to use to reclaim copper? Which factor do you think is the m

Lana71 [14]

Answer:

Aluminum

Explanation:

<h3> <em>Aluminum would be the best choice to reuse copper from the copper chloride solution because it In the aluminum–copper reaction, the chloride ions help remove the aluminum oxide coating so that a reaction can take place through the oxidation of aluminum and the reduction of copper ions.The aluminum–copper chloride reaction is a simplified version of a waste reclamation and reduction strategy for handling toxic-waste materials. </em></h3>

7 0

3 years ago

You are given a solution that is 518 mM lactose. You need to make up 4.5 L of 16.7 mM solution. What volume do you need to trans

OLga [1]

Answer:

The volume you need to transfer from the stock solution is 0.145 l

Explanation:

Since the number of moles of lactose in the volume of stock solution that you transfer will be the same as the number of moles of lactose in the final solution, you can use this expression:

number of moles in volume to transfer = number of moles in the final solution

Since number of moles = concentration * volume (if the concentration is expressed in molarity), then:

Ci * Vi = Cf * Vf

where:

Ci = concentration of the stock solution.

Vi = volume of the stock solution to be transferred.

Cf = concentration of the final solution

Vf = volume of the final solution

Then, replacing with the data:

518 mM * Vi = 16.7 mM * 4.5 l

Vi = 16.7 mM * 4.5 l / 518 mM

Notice that any concentration unit can be used, as long as the units of the concentration of the stock and final solution are the same.

4 0

3 years ago