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3 years ago

Which of the items below could scientists use to date a layer of rock?

Chemistry

1 answer:

Grace [21]3 years ago

4 0

A fossilized fish could be used to identify the date of of the rock layer.

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Give examples which indicate that nylon fibres are very strong.

Readme [11.4K]

Explanation:

is used for making ropes, used for climbing rocks and for making parachutes. Their usage shows that nylon fibres have high tensile strength

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2 years ago

Select the correct answer. Two charged objects, A and B, exert an electric force on each other. What happens if the distance bet

VikaD [51]

Answer:

The electric force between them decreases

Explanation:

The force between two charged particle is given by :

$F=\dfrac{kq_1q_2}{r^2}$

Where

r is the distance between charges

If the distance between the charges is increased, the electric force gets decreased as there is an inverse relation between force and distance.

Hence, the correct option is (c) "The electric force between them decreases"

7 0

2 years ago

The information below is a description of a substance:

skelet666 [1.2K]

Answer:

A chemical change

Explanation:

7 0

3 years ago

THIS IS A SCIENCE QUESTION

MissTica

Answer:

Explanation:

Hot air is less dense therefore it rises. Cold air is more closely packed therefore it is more dense. Less dense things rise while more dense things sink.

4 0

3 years ago

Read 2 more answers

A laboratory analysis of a sample finds it is composed of 38.8% carbon, 16.2% hydrogen, and 45.1% nitrogen. What is its empirica

Sladkaya [172]

Answer: The empirical formula for the given compound is $CH_5N$

Explanation : Given,

Percentage of C = 38.8 %

Percentage of H = 16.2 %

Percentage of N = 45.1 %

Let the mass of compound be 100 g. So, percentages given are taken as mass.

Mass of C = 38.8 g

Mass of H = 16.2 g

Mass of N = 45.4 g

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{38.8g}{12g/mole}=3.23moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{16.2g}{1g/mole}=16.2moles$

Moles of Nitrogen = $\frac{\text{Given mass of nitrogen}}{\text{Molar mass of nitrogen}}=\frac{45.4g}{14g/mole}=3.24moles$

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 3.23 moles.

For Carbon = $\frac{3.23}{3.23}=1$

For Hydrogen = $\frac{16.2}{3.23}=5.01\approx 5$

For Oxygen = $\frac{3.24}{3.23}=1.00\approx 1$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H : N = 1 : 5 : 1

Hence, the empirical formula for the given compound is $C_1H_5N_1=CH_5N$

3 0

3 years ago