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2 years ago

In Dobereiner's classification system, the atomic mass of the middle element could be estimated by

1 answer:

4 0

Dobereiner's classification system is more commonly known as Dobereiner's Triads. From the name itself, Dobereiner grouped elements into groups of three that have similar properties. According to this system, the atomic weight of the middle element is more or less the average of the atomic weights of the other two elements. So, the answer is C.

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Which of the following statements is (are) true about enzyme-catalyzed reactions? a. The reaction is faster than the same reacti

Brums [2.3K]

Answer : The correct option is A.

Explanation :

Enzyme-catalyzed reaction :

Enzyme act as a biological catalyst and the role of catalyst is to increase the rate of chemical reaction by lowering the activation energy.

Most of the chemical reactions are slow in the absence of enzyme but in the presence of enzyme, the reaction become faster. That means the Enzyme accelerate the rate of reaction.

Therefore, the correct answer is the reaction is faster than the same reaction in the absence of the enzyme.

5 0

2 years ago

Albus Dumbledore provides his students with a sample of 19.3 g of sodium sulfate. How many oxygen atoms are in this sample

Dimas [21]

Answer:

3.27·10²³ atoms of O

Explanation:

To figure out the amount of oxygen atoms in this sample, we must first evaluate the sample.

The chemical formula for sodium sulfate is Na₂SO₄, and its molar mass is approximately 142.05 $\frac{g}{mol}$ .

We will use stoichiometry to convert from our mass of Na₂SO₄ to moles of Na₂SO₄, and then from moles of Na₂SO₄ to moles of O using the mole ratio; then finally, we will convert from moles of O to atoms of O using Avogadro's constant.

19.3g Na₂SO₄ · $\frac{1 mol Na^2SO^4}{142.05g Na^2SO^4}$ · $\frac{4 mol O}{1 mol Na^2SO^4}$ · $\frac{6.022x10^2^3}{1 mol O}$

After doing the math for this dimensional analysis, you should get a quantity of approximately 3.27·10²³ atoms of O.

3 0

2 years ago

Write a hypothesis for this: Hummingbirds are attracted to the color red

Margaret [11]

Answer: I believe/don't believe hummingbirds are attracted to the color red because ... (Enter your reasons)

Explanation:

Hypothesis are always different, up to you to choose believe or not believe depending on your position.

:) Hope this helped.

8 0

2 years ago

The crystalline hydrate cd(no3)2 ⋅ 4h2o(s) loses water when placed in a large, closed, dry vessel at room temperature: cd(no3)2⋅

Sever21 [200]

The given dehydration equation is,

$Cd(NO_{3})_{2}. 4H_{2}O (s) ---> Cd(NO_{3})_{2}(s) + 4 H_{2}O(g)$

Cadmiumnitrate tetrahydrate when heated dehydrates releasing the combined water as water vapor. The reaction produces 4 moles of gaseous product water vapor. So, the degree of disorder or randomness increases. Hence, the sign of change in entropy is positive.

This reaction is spontaneous at room temperature even if it is endothermic as the sign of change in entropy is positive.

8 0

2 years ago

Read 2 more answers

Equal numbers of moles of He(g), Ar(g), and Ne(g) are placed in a glass vessel at room temperature. If the vessel has a pinhole-

mrs_skeptik [129]

Answer:

VP as function of time => VP(Ar) > VP(Ne) > VP(He).

Explanation:

Effusion rate of the lighter particles will be higher than the heavier particles. That is, the lighter particles will leave the container faster than the heavier particles. Over time, the vapor pressure of the greater number of heavier particles will be higher than the vapor pressure of the lighter particles.

=> VP as function of time => VP(Ar) > VP(Ne) > VP(He).

Review Graham's Law => Effusion Rate ∝ 1/√formula mass.

4 0

2 years ago