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2 years ago

Is the answer B or D , Help !

Chemistry

2 answers:

Dmitrij [34]2 years ago

7 0

B. it contributes electrons

Alex2 years ago

6 0

The NADPH contributions Electrons to the cycle

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A chemist measures the energy change ?H during the following reaction: 2HgO (s) ?2Hg (l) +O2 (g) =?H182.kJ Use the information t

Elan Coil [88]

Answer:

A. endothermic.

A. Yes, absorbed.

Explanation:

Let's consider the following thermochemical equation.

2 HgO(s) ⇒ 2 Hg(l) + O₂(g) ΔH = 182 kJ

The enthalpy of the reaction is positive (ΔH > 0), which means that the reaction is endothermic.

182 kJ are absorbed when 2 moles of HgO react (molar mass 216.59 g/mol). The heat absorbed when 72.8 g of HgO react is:

$72.8g.\frac{1mol}{216.59g} .\frac{182kJ}{2mol} =30.6kJ/mol$

6 0

3 years ago

Describe the three states of matter in terms of shape and volume

abruzzese [7]

Shape
A gas is shapeless all other things being equal. It will, if put in a container, occupy every part of the container.

A liquid could also be thought of shapeless. If put in a container, it need not occupy the entire container. It will occupy as much as its calculated volume will permit it to occupy.

A solid will only occupy its original shape.

Volume
A gas will occupy whatever container it is put in within limits. You cannot put a 72 mols of gas in a mm^3 container without some amazing ability to apply a lot of pressure.

A liquid will occupy a volume determined by its density and mass. In general liquids cannot be compressed.

Whatever volume a solid has to start with, it will retain that volume all other things being equal.

This is actually very hard to describe.

7 0

2 years ago

What are the terms that descripe these values for the element oxygen?

Serga [27]

Answer:

16 is the mass number. 8 is the atomic number.

5 0

2 years ago

Elements occur in a number of isotopic forms. In this problem, you will learn about the notation used to distinguish different i

alina1380 [7]

Answer:

Number of protons, Z = 14
Number of neutrons, N = 14

Explanation:

1) About isotopes:

Isotopes are different kind of atoms of the same element. Hence, they have the atomic number (Z), which is the number of protons, the same number of electrons (talking about to neutral atoms, not ions), and different number of neutrons N).

This is, it is the number of neutrons what distinguish different isotopes of an element.

2) About the notation used to distinguish different isotopes:

A superscript and a subscript, both to the left of the chemical symbol of the element, are used to distinguish different isotopes:

A ←------------- This superscript tells the mass number of the isotope

X ←--------- This is the chemical symbol of the element

Z ←-------------- This subscript is the atomic number of isotope

In our case, the notiation for the isotope of silicon is: ²⁸₁₄ Si

So, we have:

28 is the mass number (A)
14 is the atomic number (Z)
Si is the chemical symbol.

Now, you can answer the questions of the part A:

Number of protons: Z = 14

Number of neutrons N:

mass number = number of protons + number of neutrons

A = Z + N

⇒ N = A - Z = 28 - 14 = 14

In conclusion:

Number of protons, Z = 14
Number of neutrons, N = 14

5 0

3 years ago

An object has a mass of 55 grams and a density of 3.23g/ml ? what is the volume

lara [203]

Volume= mass divided by density
V= m/d
55/3.23
= 17.03

8 0

2 years ago