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4 years ago

Which of the following measurements is expressed to three significant figures?

Chemistry

2 answers:

garik1379 [7]4 years ago

8 0

The measurement that is expressed to 3 significant figures would be C. 7.30 X 10^-7.

Gelneren [198K]4 years ago

6 0

Answer: $7.30\times 10^{-7}$

Explanation :

Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

Rules for significant figures:

Digits from 1 to 9 are always significant and have infinite number of significant figures.

All non-zero numbers are always significant. For example: 654, 6.54 and 65.4 all have three significant figures.

All zero’s between integers are always significant. For example: 5005, 5.005 and 50.05 all have four significant figures.

All zero’s preceding the first integers are never significant. For example: 0.0078 has two significant figures.

All zero’s after the decimal point are always significant. For example: 4.500 have four significant figures.

All zeroes used solely for spacing the decimal point are not significant. For example : 8000 has one significant figure.

1. 0.007 has one significant figure.

2. 7077 has four significant figures.

3. $7.30\times 10^{-7}$ has three significant figures.

4. 0.070 has two significant figures.

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erastovalidia [21]

Answer:

blowing wind

Explanation:

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4 years ago

A 47.1 g sample of a metal is heated to 99.0°C and then placed in a calorimeter containing 120.0 g of water (c = 4.18 J/g°C) at

wlad13 [49]

Answer : The metal used was iron (the specific heat capacity is $0.44J/g^oC$ ).

Explanation :

In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.

$q_1=-q_2$

$m_1\times c_1\times (T_f-T_1)=-m_2\times c_2\times (T_f-T_2)$

where,

$C_1$ = specific heat of metal = ?

$C_1$ = specific heat of water = $4.18J/g^oC$

$m_1$ = mass of metal = 47.1 g

$m_2$ = mass of water = 120 g

$T_f$ = final temperature of water = $24.5^oC$

$T_1$ = initial temperature of metal = $99^oC$

$T_2$ = initial temperature of water = $21.4^oC$

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

$47.1g\times c_1\times (24.5-99)^oC=-120g\times 4.18J/g^oC\times (24.5-21.4)^oC$

$c_1=0.44J/g^oC$

Form the value of specific heat of metal, we conclude that the metal used in this was iron.

Therefore, the metal used was iron (the specific heat capacity is $0.44J/g^oC$ ).

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3 years ago

LeAnn knows the speed of an airplane but she wants to find the velocity. What does she need to determine to find velocity?

SCORPION-xisa [38]

A.
The time it takes the airplane to move between two points

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3 years ago

Two reactions and their equilibrium constants are given. A + 2 B − ⇀ ↽ − 2 C K 1 = 2.79 2 C − ⇀ ↽ − D K 2 = 0.186 Calculate the

vfiekz [6]

Answer:

K=1.93

Explanation:

Given reactions are:

A +2B ⇄ 2C K1=2.79

2C ⇄ D K2=0.186

D⇄ A+ 2B K=?

If we reverse the reaction then the euillibrium constant also become reciprocal of original value:

3rd reaction is a combination of reciprocal of 1st and 2nd reaction

2C⇄A +2B 1/K1;........................1

D ⇄ 2C 1/K2; ..............................2

On adding 1 and 2

D ⇄A +2B $K=\frac{1}{K1} \times\frac{1}{K2};$

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K=1.93

4 0

4 years ago

What factors affect the radius of an atom?

Diano4ka-milaya [45]

Answer:

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3 years ago