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3 years ago

Answer the question in image attached Thanks!

Chemistry

2 answers:

arsen [322]3 years ago

6 0

Answer: i think the 3,4,2

Explanation:

Alisiya [41]3 years ago

3 0

Answer:

i think its 2, 3 and 4

ionic and molecular compounds, polyatomic ions, ch chemical equations

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3. A sample of carbon has a mass of

Sav [38]

$- 34 {}^{15}$

The power of -34 will be 15 because 15 zeroes are given....

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3 years ago

Is a Animal and Plant cell living

Mila [183]

Yes Animal and plant are cell living

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3 years ago

If 12.5 grams of the original sample of cesium-137 remained after 90.6 years, what was the mass of the original sample?

myrzilka [38]

Answer:

Mass of original sample = 100 g

Explanation:

Half life of cesium-137 = 30.17 years

$t_{1/2}=\frac {ln\ 2}{k}$

Where, k is rate constant

So,

$k=\frac{\ln2}{t_{1/2}}$

$k=\frac{\ln2}{30.17}\ year^{-1}$

The rate constant, k = 0.02297 year⁻¹

Time = 90.6 years

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

Initial concentration $[A_0]$ = ?

Final concentration $[A_t]$ = 12.5 grams

Applying in the above equation, we get that:-

$12.5\ g=[A_0]e^{-0.02297\times 90.6}$

$[A_0]=\frac{12.5}{e^{-0.02297\times 90.6}}\ g=100\ g$

<u>Mass of original sample = 100 g</u>

8 0

3 years ago

A mileage test is conducted for a new car model. Thirty randomly selected cars are driven for a month and the mileage is measure

Leni [432]

Answer: $(27.81,\ 29.39)$

Explanation:

Given : Sample size : n= 30 , it means it is a large sample (n≥ 30), so we use z-test .

Significance level : $\alpha: 1-0.95=0.05$

Critical value: $z_{\alpha/2}=1.96$

Sample mean : $\overline{x}=28.6$

Standard deviation : $\sigma=2.2$

The formula to find the confidence interval is given by :-

$\overline{x}\pm z_{\alpha/2}\dfrac{\sigma}{\sqrt{n}}$

i.e. $28.6\pm (1.96)\dfrac{2.2}{\sqrt{30}}$

i.e. $28.6\pm 0.787259889321$

$\approx28.6\pm 0.79=(28.6-0.79,28.6+0.79)=(27.81,\ 29.39)$

Hence, the 95% confidence interval for the mean mpg in the entire population of that car model = $(27.81,\ 29.39)$

4 0

3 years ago

A sample of a substance has a mass of 7.5 g and a volume of 2.5 cubic centimeters. What is the object’s density?

Inga [223]

Answer:

option A is the correct answer .

Explanation:

as density = mass per unit volume

density = 7.5/2.5 = 3 gm / cm³ ..is the answer ...

pls mark my answer as brainlist plzzzz and plz vote

7 0

2 years ago

Read 2 more answers