1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
polet [3.4K]
3 years ago
7

Gold in its pure form is too soft to be used for most jewelry. Therefore, the gold is mixed with other metals to produce an allo

y. The composition of gold alloys are always calculated by mass, using the karat (kt) as a unit of measure. A karat represents a proportion by mass of one part in twenty-four. The higher the karat value, the higher the proportion of gold in relation to the total metal content. Pure gold is therefore 24 karat, while an 18-karat gold alloy contains (at least) 18 parts (by mass) of gold out of 24 parts total.
In a sample of 18-karat gold, 75 percent of the total mass is pure gold, while the rest is typically 16 percent silver and 9 percent copper. If the density of pure gold is rhogold = 19.3 g/cm^3, while the densitites of silver and copper are respectively rhosilver = 10.5 g/cm^3 and rhocopper = 8.90 g/cm^3.
a) What is the overall density rho18kt of this alloy of 18-karat gold?
Express your answer in grams per cubic centimeter to three significant figures.
Physics
1 answer:
Novay_Z [31]3 years ago
6 0

Answer:

Explanation:18kt alloy contains

i) 75% of gold

rhogold=19.3g/cm^3

=75/100×19.3

=14.475g/cm^3

ii) 16% of silver

rhosilver=10.5g/cm^3

=16/100×10.5

=1.68g/cm^3

iii) 9% of copper

rhocopper =8.90g/cm^3

=9/100×8.9

=0.801g/cm^3

Overall density of 18kt gold

=(0.801+1.68+14.475)g/cm^3

=16.956g/cm^3

=17g/cm^3 to 3s.f

You might be interested in
The sunlight that reaches Earth is generated by a transformation of _____.
Georgia [21]

nuclear energy

Explanation:

The sunlight that reaches earth is generated by a transformation of nuclear energy. Radiant energy is a from of energy that reaches the earth from nuclear reactions in the core of the sun.

  • In this process, light nuclei combines to form larger ones through the process of nuclear fusion.
  • This process does not conserve energy and mass is converted to energy.
  • The nuclear reaction produces huge energy that goes into the solar system space and lights it up.
  • Therefore, it is a transformation of nuclear energy into radiant energy.
  • The radiant energy is made up of electromagnetic radiations.

Learn more;

Nuclear reactions brainly.com/question/10094982

#learnwithBrainly

6 0
3 years ago
How does enormous energy get released from the sun​
vova2212 [387]

Answer:

By nuclear fission

Explanation:

<u>The sun generates enormous energy through the process of nuclear fusion.</u>

<em>The core or the innermost part of the sun is characterized by high temperature and pressure. These two factors cause the separation of nuclei from electrons and the fusion of hydrogen nuclei to form a  helium atom. </em>

During the fusion process, energy is released.

3 0
3 years ago
4. Brandon throws a tennis ball vertically upward. The ball returns to the point of release after 4.0 s. What is the
vekshin1

Answer:

-39.2m/s

Explanation:

Using the equation of motion;

v = u + at

Since the ball is thrown upward, the acceleration due to gravity acting on it will be negative, hence a = -g

v = u - gt

Since g = 9.8m/s²

t = 4.0s

u = 0m/s

v = 0 + (-9.8)(4)

v = 0 + (-9.8)(4)

v = -39.2m/s

Hence the speed of the ball before release is -39.2m/s

6 0
2 years ago
You hold a ruler that has a charge on its tip 6 cm above a small piece of tissue paper to see if it can be picked up. The ruler
scZoUnD [109]

Answer:

q=1.4*10^{-9}C

Explanation:

Given data:

charge on ruler = -14μC

Mass of tissue is 5 g

To Know the minimum charge,  equate electrostatic force to weight  

we have F = W

so\frac{KQq}{r^2} =mg

putting all value in equation,

=\frac{9*10^9*(14*10^{-6})*q}{0.06^2} = 5* 10^{-3}*9.8

solving for q

q =\frac{5* 10^{-3}*9.8 *0.06^2}{9*10^9*(14*10^{-6})}

or q=1.4*10^{-9}C

5 0
3 years ago
A bus travels east for 3 km, then north for 4 km. What is its final displacement?
ikadub [295]
5 km northeast. Left and up would make northeast

8 0
3 years ago
Other questions:
  • When lost fluid is not replaced adequately can result
    9·1 answer
  • How to find the frictional force acting on an object (not the friction coefficient)? ...?
    6·1 answer
  • Which of these geologic events is most closely associated with a transform plate boundary?
    9·1 answer
  • Which best describes a material with a low index of refraction (near 1)?
    15·2 answers
  • Which example best describes a restoring force?
    7·1 answer
  • Two particles, one with charge − 7.97 μC and one with charge 3.55 μC, are 6.59 cm apart. What is the magnitude of the force that
    10·1 answer
  • I. WILL. GIVE. BRAINLEIEST. IF. YOU. GET. THIS. RIGHT!!!<br><br>What is ozone? science
    12·2 answers
  • Which of these is true of all simple machines?
    15·1 answer
  • A -ion (negative ion, one with extra negative charge )
    10·2 answers
  • if 16,700 j of work is done to shoot the human cannonball down a 30.5m barrel,then how much force is applied to the person to fi
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!