Ask question

Ask question

All categories

Amiraneli [1.4K]

1 year ago

5

In the video, the water level was 15 milliliters before adding the chain, and 20 milliliters after adding the chain. When I weig

hed the chain, its mass was 76.3 grams.
I believe the chain is solid metal (not gold plated), but is probably a blend of gold and other metals. I looked up that gold has a density of 19.3 g/ml, while the other metals like silver and copper usually blended with gold have a combined density of about 9.7 g/ml.

Determine what percentage of the chain is gold, by mass, to at least 1 decimal place?

2 answers:

BartSMP [9]1 year ago

6 0

345 g / ml I hope this helps you !

beks73 [17]1 year ago

3 0

Answer:39.7%

Step-by-step explanation:

1. First find the density of your chain

Density = mass / volume

Volume = displaced water volume

= Volume of Final level of water - initial level of water

= 20 ml - 15 ml = 5 ml

Mass = 66.7 g

Density = 66.7g / 5 ml = 13.34 g/ml

2. Second, write the denisty of the chain as the weighted average of the densities of the other metals:

Mass of gold × density of gold + mass of other metals × density of other metals, all divided by the mass of the chain.

Calling x the amount of gold, then the amount of other metals is 66.7 - x:

Then, there are 26.47 grams of gold in 66.7 grams of chain, which yields a percentage of:

(26.47 / 66.7) × 100 = 39.7%1. First find the density of your chain

Density = mass / volume

Volume = displaced water volume

= Volume of Final level of water - initial level of water

= 20 ml - 15 ml = 5 ml

Mass = 66.7 g

Density = 66.7g / 5 ml = 13.34 g/ml

2. Second, write the denisty of the chain as the weighted average of the densities of the other metals:

Mass of gold × density of gold + mass of other metals × density of other metals, all divided by the mass of the chain.

Calling x the amount of gold, then the amount of other metals is 66.7 - x:

Then, there are 26.47 grams of gold in 66.7 grams of chain, which yields a percentage of:

(26.47 / 66.7) × 100 = 39.7%

You might be interested in

HJ is twice JK. J is between H and K. If HJ= 4x and HK=78, find Jk.

ss7ja [257]

You'll find it easier to understand if you illustrate the problem as what is shown in the attached picture. From the illustration and the problem description, two equations can be formulated:

HJ = 2JK
HJ + JK = HK

2JK + JK = 78
3JK = 78
JK = 78/3
JK = 26

6 0

2 years ago

Based on the graph shown to the right, whose phones cost varies directly with the amount of time spent talking?

Lena [83]

Answer:

B

Step-by-step explanation:

Given 2 quantities that vary directly, then the graph must pass through the origin.

Nikiya's graph is the only one to do this ⇒ B

8 0

1 year ago

Read 2 more answers

Eighty percent of one store's customers paid with credit cards. Forty customers came in that day. How many customers paid for th

mario62 [17]

80%=.8

40*.8=32

32 people made their purchases with credit cards.

6 0

2 years ago

Read 2 more answers

The manufacturer of hardness testing equipment uses steel-ball indenters to penetrate metal that is being tested, however, the m

masha68 [24]

Answer:

$1.667-2.31\frac{1.803}{\sqrt{9}}=0.2789$

$1.667+2.31\frac{1.803}{\sqrt{9}}=3.055$

So on this case the 95% confidence interval would be given by (0.2789;3.055)

The 95% confidence interval to judge whether the two indeners result in different measurements is?

Yes the confidence interval not contains the value 0 so we can conclude that the values for Diamond are significantly higher than the values for Steel Ball at 5% of significance.

Step-by-step explanation:

We have the following dataset:

specimen 1 2 3 4 5 6 7 8 9

Steel Ball 51 57 61 70 68 54 65 51 53

Diamond 53 55 63 74 69 56 68 51 56

If we calculate the differences diamond-steel ball we have this datase:

d: 2, -2, 2, 4, 1, 2, 3, 0, 3

The second step is calculate the mean difference

$\bar d= \frac{\sum_{i=1}^n d_i}{n}=1.667$

The third step would be calculate the standard deviation for the differences, and we got:

$s_d =\frac{\sum_{i=1}^n (d_i -\bar d)^2}{n-1} =1.803$

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=9-1=8$

Since the confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,9)".And we see that $t_{\alpha/2}=2.31$ .

Now we have everything in order to replace into formula (1):

$1.667-2.31\frac{1.803}{\sqrt{9}}=0.2789$

$1.667+2.31\frac{1.803}{\sqrt{9}}=3.055$

So on this case the 95% confidence interval would be given by (0.2789;3.055)

The 95% confidence interval to judge whether the two indeners result in different measurements is?

Yes the confidence interval not contains the value 0 so we can conclude that the values for Diamond are significantly higher than the values for Steel Ball at 5% of significance.

4 0

2 years ago

PLS HELP DUE IN 1 HOUR WILL GIVE BRAINLIEST THANKS AND 5 STARSSS!!!

Alenkinab [10]

Step-by-step explanation:

-2x - 10 = 14x - 7

-10 + 7 = 14x +2x

-3 = 16x

-3/16 =x

7 0

1 year ago