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Phantasy [73]
3 years ago
9

What is the differnce between the atomic number and the mass number of an element?

Chemistry
1 answer:
MrRissso [65]3 years ago
8 0
Atomic number refers to the number of protons within the nuclei of an element's atoms (and therefore the number of electrons) while mass number refers to the number of protons and neutrons within the nucleus.
You might be interested in
In a DNA molecule, if 38% of the molecular bases are C (cytosine), what percent of the bases are T (thymine)?
andreyandreev [35.5K]

Answer:

thymine is 19%

Explanation:

Acc to Chargaff's rule, amount of Adenine= amount of Thymine as well as amount of Guanine= amount of Cytosine. Amount left for Thymine and Adenine is 38% now. Since both Adenine and Thymine are, again in equal quantities, so therefore percentage of thymine is 19%.

8 0
3 years ago
The relationship between the pitcher plant and the insects is an example of (competition/predation/symbiosis).
Tresset [83]
Predation, because the pitcher plant is preying on the insects.
4 0
3 years ago
Read 2 more answers
A rock face at the top of a mountain is composed of layers in which seashells are embedded. This type of rock is ​
Allushta [10]

Answer:

Sedimentary rock.

Explanation:

When limestone form as ocean water evaporates and leaves calcium carbonate behind, they are then deposited in the seabed. Thus, the type of rock that can be formed this way is a sedimentary rock.

The texture of organic land-derived sedimentary rocks is fragmental or clastic. Sediments come from living organisms such as plants and animals to form organic sedimentary rocks.

Some examples of inorganic land-derived sedimentary rocks are conglomerate, brescia and sandstone.

In this scenario, a rock face at the top of a mountain is composed of layers in which seashells are embedded. This type of rock is a sedimentary rock.

7 0
2 years ago
A buffer solution contains 0.486 M NaHCO3 and 0.345 M Na2CO3. If 0.0321 moles of sodium hydroxide are added to 150 mL of this bu
Molodets [167]

Answer:

pH = 10.51

Explanation:

The buffer of HCO₃⁻ + CO₃²⁻ has a pka of 10.2

HCO₃⁻ ⇄ H⁺ + CO₃²⁻

0,150L of these substances are:

0,150L × 0,486M NaHCO₃ = <em>0.0729mol NaHCO₃</em>

0,150L × 0,345M Na₂CO₃ = <em>0.05175mol Na₂CO₃</em>

NaOH reacts with HCO₃⁻ producing CO₃²⁻, thus:

NaOH + HCO₃⁻ → CO₃²⁻ + H₂O + Na⁺

0.0321 moles of NaOH produce the same moles of CO₃²⁻ and consume HCO₃⁻. Moles of these species are:

CO₃²⁻: 0.05175mol + 0.0321mol: <em>0.08385mol</em>

HCO₃⁻: 0.0729mol - 0.0321 mol: <em>0.0408mol</em>

<em />

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.08385mol / 0.0408mol

<em>pH = 10.51</em>

<em />

I hope it helps!

7 0
3 years ago
How many moles are needed to make 2.5 L of a 3.8 M solution?
erik [133]

Answer:

9.5

Explanation:

that the answer I hope am correct

4 0
2 years ago
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