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3 years ago

1. The elements on the Periodic Table are arranged in order of increasing

Chemistry

2 answers:

s344n2d4d5 [400]3 years ago

8 0

Answer:

Atomic number

Explanation:

eduard3 years ago

8 0

Answer:

Atomic number

Explanation:

In the modern periodic table, the elements are listed in order of increasing atomic number. The atomic number is the number of protons in the nucleus of an atom.

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Equations can be balanced by using the half-reaction method. Which step should be completed first when using this method?

Tamiku [17]

Answer:

Separate the reaction into half equations

Explanation:

When we want to balance redox equations, we must take cognizance of the fact that a specie was oxidized and another specie was reduced.

Hence we must identify the specie that was oxidized and the one that was reduced and then break up the whole redox reaction into oxidation and reduction half equations.

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3 years ago

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What is the term for the smallest bit into which a chemical substance can be divided and still have the properties of that subst

ziro4ka [17]

Answer:

Molecule

Explanation:

molecule of the substance. You can break the molecule down further, into the atoms that make it up, but those don't have the properties of the original 'compound'.

Here's an example:

-- Sodium is a soft, slippery metal, that explodes when water touches it.

-- Chlorine is a poisonous green gas.

When an atom of Sodium and an atom of Chlorine combine, they make one molecule of a substance called "Sodium Chloride". That's SALT ! It isn't green, it isn't a gas, it isn't poisonous, it isn't soft and slippery, and it doesn't explode when water touches it.

3 0

3 years ago

In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an ex

Kay [80]

The question is incomplete. The complete question is :

In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an explanation that tells how much NaOH needs to be added to a beaker of HCl to cause the color to change. Your explanation can be something like: The color change will occur when [some amount] of NaOH is added because the color change occurs when [some condition]. The goal for your explanation is that it describes the outcome of this example, but can also be used to predict the outcome of other examples of this phenomenon. Here's an example explanation: The color of the solution will change when 40 ml of NaOH is added to a beaker of HCl because the color always changes when 40ml of base is added. Although this explanation works for this example, it probably won't work in examples where the flask contains a different amount of HCl, such as 30ml. Try to make an explanation that accurately predicts the outcome of other versions of this phenomenon.

Solution :

Consider the equation of the reaction between NaOH and $HCl$

NaOH (aq) + HCl (aq) → NaCl(aq) + $H_2O (l)$

The above equation tells us that $1 \text{mole}$ of $NaOH$ reacts with $1 \text{mole}$ of $HCl$ .

So at the equivalence point, the moles of NaOH added = moles of $HCl$ present.

If the volume of the $HCl$ taken = $V_1$ mL and the conc. of $HCl$ = $M_1$ mole/L

The volume of NaOH added up to the color change = $V_2 \text{ and conc of NaOH = M}_2$ mole/L

Moles of $HCl$ taken = $V_1 \ mL \times M_1 \ mol/100 \ mL = V_2M_2 \times 10^{-3}$ moles.

The color change will occur when the moles of NaOH added is equal to the moles of $HCl$ taken.

Thus when $V_1 M_1 \times 10^{-3} = V_2M_2 \times 10^{-3}$

or when $V_1M_1 = V_2M_2$

or $V_2=\frac{V_1M_1}{M_2}$ mL of NaOH added, we observe the color change.

Where $V_1, M_1$ are the volume and molarity of the $HCl$ taken.

$M_2$ is the molarity of NaOH added.

When both the NaOH and $HCl$ are of the same concentrations, i.e. if $M_1=M_2$ , then $V_2=V_1$

Or the 40 mL of $HCl$ will need 40 mL of NaOH for a color change and

30 mL of $HCl$ would need 30 mL of NaOH for the color change (provided the concentration $M_1=M_2$ )

7 0

3 years ago

How do dominate and recessive alleles differ?

ch4aika [34]

Hi , basically dominant alleles are always expressed in the organism , while recessive traits tend to be expressed only when the dominant allele is not present.

3 0

3 years ago

QUICK HELP PLEASE!!?? Need answer QUICK

d1i1m1o1n [39]

Answer:

Explanation:

Look on the x-axis for the tick marked "60". This indicates 60 degrees Celsius, which we want. Now, look on the y-axis for the tick marked "60". This indicates 60 grams of $Na_2HAsO_4$ . Trace along the graph to find where these two places meet at (60, 60).

Now, look for the solubility curve of $Na_2HAsO_4$ ; it's the yellow-orange line. Find out what the y-coordinate of the point where x = 60 is on the line: it's around (60, 65).

So, since the point (60, 60) is below the line corresponding to this substance, $Na_2HAsO_4$ is unsaturated.

The answer is B.

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3 years ago

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