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2 years ago

If you have a 100g of Boron and you want to find out how

Chemistry

1 answer:

Dmitry [639]2 years ago

7 0

Answer:

5.57 x 10^24 atoms

Explanation:

first, you are seeking the number of ATOMS of Boron.

Boron has an Atomic mass of 10.8 g/mol (see #5 on the periodic table)

100 gm of Boron would have 100 g /10.8 g/mol =9.26 moles

each mole has Avogadros number of atoms 6.02 x 10^23

9.26 moles has 9.26 x 6.02 x 10^23 atoms =5.57 x 10^24 atoms

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What is the potential energy of 25kg rock sitting on the cliff with a height of 230m?

My name is Ann [436]

Answer:

Explanation:

The potential energy of a body can be found by using the formula

PE = mgh

where

m is the mass

h is the height

g is the acceleration due to gravity which is 10 m/s²

From the question we have

PE = 25 × 10 × 230 = 57,500

We have the final answer as

Hope this helps you

5 0

1 year ago

Consider the following first-order reaction: A → B. The concentration of A at the start of the reaction is 4.17 M and after 4.84

valina [46]

Answer : The value of rate constant is, $0.0327s^{-1}$

Explanation :

First we have to calculate the rate constant, we use the formula :

Expression for rate law for first order kinetics is given by:

$k=\frac{2.303}{t}\log\frac{a}{a-x}$

where,

k = rate constant = ?

t = time passed by the sample = 4.84 s

a = initial concentration = 4.17 M

a - x = concentration after time 4.84 s = 3.56 M

Now put all the given values in above equation, we get

$k=\frac{2.303}{4.84}\log\frac{4.17}{3.56}$

$k=0.0327s^{-1}$

Therefore, the value of rate constant is, $0.0327s^{-1}$

4 0

2 years ago

C=h/[M(T2-T1)] solve for T1

vodka [1.7K]

Explanation:

This is expressing as a subject of a formula of a specie.

This equation is used in solving for specific heat capacity of a material;

equation:

c = $\frac{h}{M(T2 - T1)}$

First cross multiply:

c[M(T2 - T1)] = h

Then multiply both sides by $\frac{1}{c }$ :

$\frac{1}{c }$ x c[M(T2 - T1)] = $\frac{1}{c }$ x h

M(T2 - T1) = $\frac{h}{c}$

Multiply both sides by $\frac{1}{M}$

$\frac{1}{M}$ x M(T2 - T1) = $\frac{1}{M} x \frac{h}{c}$

T2 - T1 = $\frac{h}{Mc}$

Now rearrange to produce;

T1 = T2 + $\frac{h}{Mc}$

learn more:

Specific heat brainly.com/question/7210400

#learnwithBrainly

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2 years ago

Which equation correctly relates the heat of reaction to the standard heats of formation?

VARVARA [1.3K]

Answer:

Explanation:

∆H° = ∆Hf ° (products) – ∆Hf ° (reactants)

4 0

2 years ago

Burning a piece of wood in fire can be best described as a chemical change because the atoms in wood change their state. physica

Phoenix [80]

The answeris c, chemicalchange because the atoms in woodand oxygen are rearranged.

6 0

2 years ago

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