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3 years ago

Calculate the mass in grams for 0.251 moles of Na2CO3

Chemistry

1 answer:

Len [333]3 years ago

5 0

Answer:

Explanation:

the molar mass for Na2CO3 is 2*23+12+3*16=106 g/mole

106*0.251=26.606 grames

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The metallic radius of an aluminum atom is 143 pm. What is the volume of an aluminum atom in cubic meters?

Marina86 [1]

Answer:

6.61 × 10∧-29 m³

Explanation:

Given data:

Atomic radius= 143 pm = 143 × 10∧-12 m

volume = ?

Formula:

r = a/2√2

143 × 10∧-12 m = a/ 2√2

a= 143 × 10∧-12 m × 2√2

a= 404.4 × 10∧-12 m

where a is edge length, so we can calculate the volume by using following formula:

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V= (404.4 × 10∧-12 m)³

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4 years ago

Suppose that you place exactly 100 bacteria into a flask containing nutrients for the bacteria and that you find the following d

tresset_1 [31]

Answer:

The order of the production of bacteria is 1.

12,787 bacteria will be present after 112 min.

$0.04331 min^{-1}$ is the rate constant for the process.

Explanation:

Rate of formation of bacteria when there 100 bacteria: R

Rate of formation of bacteria when there 200 bacteria: R' =2R

Rate of formation of bacteria is directly proportional to the number of bacteria:

$\frac{R}{R'}=\frac{k[200]^x}{k[400]^x}$

$\frac{R}{2R}=(\frac{200}{400})^x$

x = 1

The order of the production of bacteria is 1.

The half life of the process = $t_{1/2}=16 minutes$

Rate constant of the process = k

For first order process k is only dependent on half life:

$k=\frac{0.693}{t_{1/2}}$

$k=\frac{0.693}{16 min}=0.04331 min^{-1}$

For the first order process the increment numbers is given ;

$N=N_o\times e^{kt}$

Where:

$N_o$ = Initial population

N = Population after time t.

We have ;

$N_o=100$

t = 112 minutes

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12,787 bacteria will be present after 112 min.

$0.04331 min^{-1}$ is the rate constant for the process.

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3 years ago

Endler's Guppies Experiment on Natural Selection

Morgarella [4.7K]

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The scientific method is a series of step used to validate evidence and thus formulate theories.

Darwin used the scientific method to draw conclusions about the main mechanism of evolution, i.e., natural selection.

The scientific method involves making a question, providing an explanation of the hypothesis, making observations/experiments (which include experimental and control groups), and drawing conclusions.

The empirical data serve to test a hypothesis (either confirm or reject it) by contrasting its results with predictive outcomes.

The strength of the conclusions can be enhanced by using supporting evidence from other research fields (in this case, for example, the fossil record).

In conclusion, an experiment on Natural Selection includes mechanisms (question), explanation (hypothesis), estimation of the frequency of the trait in the population (prediction) and comparisons (control group).

Learn more about the scientific method here:

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2 years ago

1. A sample of gas has an initial volume of 25 L and an initial pressure of 123.5 kPa. If the pressure changes to

sveta [45]

Answer:

$\large \boxed{\text{17.mL}}$

Explanation:

The temperature and amount of gas are constant, so we can use Boyle’s Law.

$p_{1}V_{1} = p_{2}V_{2}$

Data:

$\begin{array}{rcrrcl}p_{1}& =& \text{123.5 kPa}\qquad & V_{1} &= & \text{25 L} \\p_{2}& =& \text{179.9 kPa}\qquad & V_{2} &= & ?\\\end{array}$

Calculations:

$\begin{array}{rcl}123.5 \times 25 & =& 179.9V_{2}\\3088 & = & 179.9V_{2}\\V_{2} & = &\dfrac{3088}{179.9}\\\\& = &\textbf{17 L}\\\end{array}\\\text{The new volume of the gas is } \large \boxed{\textbf{17 L}}$

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3 years ago

HELP LAST QUESTION WILL MAKE BRAINLIEST

Alenkasestr [34]

Answer:

I think it is C.)????

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3 years ago

Calculate the mass in grams for 0.251 moles of Na2CO3￼

Calculate the mass in grams for 0.251 moles of Na2CO3