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2 years ago

Calculate the number of ammonia molecules in 3.9 g.

1 answer:

6 0

•3.9g of ammonia
•molar mass of ammonia = 17.03g/mol

1st you have to covert grams to moles by dividing the mass of ammonia with the molar mass:

(3.9 g)/ (17.03g/mol) = 0.22900763mols

Then convert the moles to molecules by multiplying it with Avogadro’s number:

Avogadro’s number: 6.022 x 10^23

0.22900763mols x (6.022 x 10^23 molecs/mol)
= 1.38 x 10^23 molecules

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A student is shown a simple model of particles that make up a liquid,as shown.

trapecia [35]

Answer:
Option-D : <span>Decrease the velocities of the particles, and decrease the space between the particles.

Explanation:
The solid state of matter is composed of particles closely packed with a minimum space between them. This closed packing of particles occur due to strong interatomic or intermolecular interactions between particles. Therefore, solids particles have zero translational and rotational motions and only show vibrational motions. So, decrease in velocity and decrease in space between particles is the right answer for making solids.</span>

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3 years ago

if you take a dried out white rose and place the stem in food coloring, will the rose turn the color you put the stem in

cricket20 [7]

Answer:

Yes, this is true. The reason is that the flower transpires and sucks the water in and distributes it as much as it can. You can also flip it upside down and hang it with petals down , allowing the liquid to enter the flower and then retaining color for longer periods of time and having more color.

Explanation:

7 0

2 years ago

A mixture of 454 kg of applesauce at 10 degrees Celsius is heated in a heat exchanger by adding 121300 kJ. Calculate the outlet

stira [4]

Explanation:

The given data is as follows.

Mass of apple sauce mixture = 454 kg

Heat added (Q) = 121300 kJ

Heat capacity ( $C_{p}$ ) of apple sauce at $32.8^{o}C$ = 4.0177 $kJ/kg^{o}C$

So, Heat given by heat exchanger = heat taken by apple sauce

Q = $mC_{p} \Delta T$

or, Q = $mC_{p} (T_{f} - T_{i})$

Putting the given values into the above formula as follows.

Q = $mC_{p} (T_{f} - T_{i})$

121300 kJ = $454 kg \times 4.0177 kJ/kg^{o}C \times (T_{f} - 10)$

$T_{f}$ = $76.5^{o}C$

Thus, we can conclude that outlet temperature of the apple sauce is $76.5^{o}C$ .

3 0

3 years ago

How many moles in 4.93 x 10E23 atoms of silver?

leva [86]

<h3>Answer:</h3>

0.819 mol Ag

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right<u> </u>

<u>Chemistry</u>

<u>Atomic Structure</u>

Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

<u>Stoichiometry</u>

Using Dimensional Analysis

<h3>Explanation:</h3>

<u>Step 1: Define</u>

4.93 × 10²³ atoms Ag

<u>Step 2: Identify Conversions</u>

Avogadro's Number

<u>Step 3: Convert</u>

Set up: $\displaystyle 4.93 \cdot 10^{23} \ atoms \ Ag(\frac{1 \ mol \ Ag}{6.022 \cdot 10^{23} \ atoms \ Ag})$
Divide: $\displaystyle 0.818665 \ mol \ Ag$

<u>Step 4: Check</u>

<em>Follow sig fig rules and round. We are given 3 sig figs.</em>

0.818665 mol Ag ≈ 0.819 mol Ag

8 0

2 years ago

Someone please help i don’t have much time left

REY [17]

Answer: Energy of reactants = 30, Energy of products = 10

Exothermic

Activation energy for forward reaction is 10.

Explanation:

Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and $\Delta H$ for the reaction comes out to be negative.

Energy of reactants = 30

Energy of products = 10

Thus as energy of the product < energy of the reactant, the reaction is exothermic.

Activation energy $(E_a)$ is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.

$E_a$ for forward reaction is (40-30) = 10.

6 0

2 years ago