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elena55 [62]
3 years ago
10

Which of the following is a description of an exothermic reaction?

Chemistry
1 answer:
zlopas [31]3 years ago
8 0
I think the best one is B
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Type the correct answer in the box. Express your answer to three significant figures. Calcium nitrate reacts with sodium phospha
RoseWind [281]

6.07 grams is the theoretical yield of calcium phosphate (Ca₃(PO₄)₂).

<h3>How we calculate mass from moles?</h3>

Mass of any substance can be calculated by using moles as:

n = W/M, where

W = required mass

M= molar mass

Given chemical reaction is:

3Ca(NO₃)₂ + 2Na₃PO₄ → 6NaNO₃ + Ca₃(PO₄)₂

From the stoichiometry it is clear that:

3 moles of Ca(NO₃)₂ = produce 1 mole of Ca₃(PO₄)₂

Given mass of Ca(NO₃)₂ = 96.1g

Mole of Ca(NO₃)₂ = 96.1g/164g/mol = 0.5859moles

So, 0.5859 moles of Ca(NO₃)₂ = produce 0.5859×1/3 = 0.0196 moles of Ca₃(PO₄)₂

Required mass of Ca₃(PO₄)₂ will be calculated by using moles as:

W = 0.0196mole × 310g/mole = 6.07 grams

Hence, 6.07 grams is the theoretical yield of calcium phosphate.

To know more about moles, visit the below link:

brainly.com/question/15373263

7 0
2 years ago
Help me please <br> Answer &amp; exp.
nordsb [41]

Explanation:

Some Rules Regarding Oxidation Numbers:

- Hydrogen has oxidation number of + 1 except in hydrides where it is -1

- Oxygen has oxidation number of -2 except in peroxides where it is -1

- Some elements have fixed oxidation numbers. E.g Halogen group elements has oxidation number of -1

- Oxidation number of a compound is the sum total of the individual elements and a neutral  compound has oxidation number of 0.

A. HI

Hydrogen has oxidation of + 1

Oxidation number of I:

1 + x = 0

x = -1

B. PBr3

Br has oxidation number of - 1

Oxidation number of Pb:

x + 3 (-1) = 0

x = + 3

C. KH

Hydrogen has oxidation of + 1

Oxidation number of K:

1 + x = 0

x = -1

D. H3PO4

Hydrogen has oxidation number of + 1

Oxygen has oxidation number of -2

Oxidation number of P:

3(1) + x + 4(-2) = 0

3 + x - 8 =0

x = 5

8 0
3 years ago
Dry air (0% humidity) is approximately 78% N2, 21% O2, and 1% Ar by moles. Calculate the molar mass and density of dry air at 0
ser-zykov [4K]
Shdhdhdhdhdhshshhzshshshdhdhshd
7 0
3 years ago
Use the drop-down menus to complete the statements
Kipish [7]

Answer:

First one: group

Second one: period

Third one: number of valence electrons

Last one: increases

3 0
3 years ago
Newton's second law of motion is F = ma.
ZanzabumX [31]

<u>Answer:</u> The acceleration of the object is 2m/s^2. If net force increases, acceleration will also increase and if mass increases, the acceleration will decrease.

<u>Explanation:</u>

Force is defined as the product of object's mass and acceleration.

Mathematically,

F = ma     ......(1)

or,

a = F/m      .....(2)

where,

F = Force exerted on an object = 60N

m = mass of an object = 30kg

a = acceleration of the object = ?

Putting values in above equation, we get:

a = 60 kg.m/s^2/30 kg = 2m/s^2

The acceleration of the car is 2m/s^2.

From equation 2, it is visible that acceleration is directly proportional to force. This means that \if force increases, acceleration also increases.

And acceleration is inversely proportional to mass of the object. This means that if mass increases, the acceleration decreases.

Hence, if net force increases, acceleration will also increase and if mass increases, the acceleration will decrease.

7 0
3 years ago
Read 2 more answers
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