What element is in group 2 and period 4?

Answers

Answer 1

Answer:

Calcium

Explanation:


Related Questions

A student estimated a mass to be 275 g but upon carefully measuring it found the actual mass to be 260 g. what is the percent error in the estimation?

Answers

Answer:

5.77% Error.

Explanation:

Given an experimental value of 275 g , and a theoretical value of 260 g, the percent error can be found using the equation:

[tex]\% \: error \: = \frac{ |theoretical \: value \: - \: experimental \: value | }{theoretical \: value} \times 100[/tex]

% Error = ( | 260 - 275 | / 260 ) × 100 = ( | - 15 | / 260 ) × 100 = ( 15 / 260 ) × 100 = 1500/260 = 300 / 52 = 5.769230769230.. ≈ 5.77%

A researcher wants to refine an investigation to determine the effectiveness of an enzyme at various temperatures. Which of the following would best help the researcher determine how well the enzyme is working? Question 20 options: The researcher should measure the difference in temperature during the reaction. The researcher should measure the difference in the amount of product at the beginning of the reaction. The researcher should measure the difference in the amount of enzyme remaining after the reaction. The researcher should measure the difference in the amount of product at the end of the reaction.

Answers

Answer:

The researcher should measure the difference in the amount of product at the end of the reaction.

Explanation:

Enzymes are defined as the protiens that are responsible for increasing the rate of reaction.

With the increase in temperature, the enzyme activity increases and so the rate of reaction increases. It means at lower temperature the rate of reaction decreases and the amount of product also decreases.

So, to determine the effectiveness of an enzyme at various temperatures, the difference in the amount of the product at the end of reaction should be measured.

Hence, the correct answer is "D".


Which statement describes the general process of diffusion?
Molecules move from inside of the cell to outside of the cell.
Molecules start out unevenly distributed and end up evenly distributed.
Molecules start out evenly distributed and end up unevenly distributed.
Molecules move from outside of the cell to inside of the cell.

Answers

Answer:

Molecules start out unevenly distributed and end up evenly distributed.

Explanation:

Diffusion is the process by which molecules of a substance move from a region of higher concentration to a region of lower concentration until equilibrium is attained.

Molecules start out unevenly distributed and end up evenly distributed in a particular medium. Diffusion occurs due to the particulate nature of matter. When the particles that make up a substance are concentrated at a point, the collide more often with one another causing each molecule to spread out in order to occupy all the available space.

Diffusion occurs in gases, liquids and solids but occurs fastest in gases. Diffusion can be observed for example, in the spread of the smell of a dead rat from one point in a room to every part of the room.

Answer:

B

Explanation:

:D

. The freezing point of an aqueous solution containing a nonelectrolyte solute is – 2.79 °C. What is the boiling point of this solution?

Answers

Answer:

Boiling point of the solution is 100.78°C

Explanation:

This is about colligative properties.

First of all, we need to calculate molality from the freezing point depression.

ΔT = Kf . m . i

As the solute is nonelectrolyte, i = 1

0°C - (-2.79°C) = 1.86 °C/m . m . 1

2.79°C / 1.86 m/°C = 1.5 m

Now, we go to the boiling point elevation

ΔT = Kb . m . i

Final T° - 100°C  =  0.52 °C/m . 1.5m . 1

Final T° =  0.52 °C/m . 1.5m . 1  + 100°C → 100.78°C

how many seconds are there in 45 days?

Answers

In 45 days there are 3888000 seconds.

Answer:3,888,000seconds

Explanation:

60secx60minsx24 hoursx45days=3,888,000

120mg=______g please help

Answers

Answer:

0.12

Explanation:

Cuz you divide the mass value by 1000.

Much Smort (I look up on internet)

What is the speed of an object that moves 100 meters in 5 seconds?

Answers

Answer:

speed= distance/time

= 100/5=20mph

Which of the following is a property of a pure substance?

It consists of different types of compounds.

It may have substances in different states of matter.

The ratio of the particles that make it up is fixed.

Its components can be separated by employing physical methods.

Answers

Answer:

The ratio of the particles that make it up is fixed

Explanation:

Craik and Lockhart (1972) proposed the idea that deeper levels of ____ results in stronger retention of memories

A. Rehearsal
B. Multitasking
C. Memory
D. Processing

Answers

Answer: D. Processing

Explanation: 100% on topic test also its in my e notes.

Craik and Lockhart has proposed theory of memory processing. Thus, option D is correct.

Craik and Lockhart proposed the theory for the processing of the level of memory. The memory in humans can be sensory memory, working memory, and long-term memory.

The long term memories have been stored in the deeper cells and the increased or strong stimulation of the processing results in the stronger retention of the memories. Thus, option D is correct.

For more information about the memory processing, refer to the link:

https://brainly.com/question/6249980

Describe how the proton, electron and neutron were experimentally discovered.

Answers

The discovery of protons can be attributed to Rutherford. ... Given the discoveries of electrons in 1897 by Thomson, Rutherford and other scientists decided that a positively charged particle must exist to center the electron to create equally neutral atoms. Thomson proposed the name 'positive rays'.

2. A golden-colored cube is handed to you. The person wants you to buy it for
$100, saying that it's a gold nugget. You pull out your old geology text and
look up gold in the mineral table, and read that its density is 19.3 g/cm3. You
measure the cube and find that it is 2 cm on each side, and has a mass of 40g.
What is its density? Is it gold? Should you buy it?

Answers

Answer:

Volume of the cube is 2*2*2 = 8cm^3.

Divide the weight (40g) over the volume (8cm^3).

Density is 5g/cm^3. Definitely not gold.

Explanation:

Yes, the given golden-colored cube is gold .The density of gold is 32 gm/cm³ and we must buy it.

What do you mean by density?

Density is a  mass of a unit volume of a material substance.

The formula for density is d = M/V, where d is density, M is mass, and V is volume.

Density is commonly expressed in units of grams per cubic centimetre.

To calculate density-

given

mass=40gm

side of cube =2cm

therefore, volume=(side)³

=8cm³

density=?

density=mass/volume

density=40/8

density=5 gm/cm³

The handed golden-colored cube is gold with its density 5gm/cm³ and  hence we must buy it.

Learn more about density ,here:

https://brainly.com/question/15164682

#SPJ2

You have a different rock with a volume of 30cm and a mass of 60g, What is its density?

Answers

Density = mass/volume

Therefore,
Density = 60g/30cm

i'll GIVE BRAINLY

5. Label the following measurement by the quantity it represents: 37 s * A. Density B. Time C. Temperature D. Distance

Answers

Answer:

Hey there!

35 s represents time.

The s means "seconds."

Let me know if this helps :)

Use the table to identify the phase and phase changes of the elements under the given conditions. Write the name of the substance, phase, or phase change.

When the temperature in a room increases from
25°C to 33°C,
changes from a solid
to a liquid.
In a lab, methane and nitrogen are cooled from
-170°C to -200°C. The methane freezes and the
nitrogen
.
When gold is heated to 2,856°C it changes from a liquid to a
.

Answers

Answer: gallium, condenses, gas

Explanation: took assignment on edge

Answer: gallium, condenses, gas

Explanation: took assignment on edge

During respiration, energy is retrieved from the high-energy bonds found in certain organic molecules. Which of the following, in addition to energy, are the ultimate products of respiration?
(a) CO2, H2O
(b) CH3, H2O
(c) CH2OH, O2
(d) CO2, O2

Answers

Answer:

(A.) CO2, H2O

Explanation:

The chemical equation for respiration process is:

[tex]C_{6}H_{12} O_{6}[/tex] + [tex]6O_{2}[/tex] → [tex]6CO_{2}[/tex] + [tex]6H_{2} O[/tex] + ATP↑

Energy is released during the biochemical process in the organism's cells in form of ATP. Byproducts of the reaction are carbon dioxide and water molecules.

Let me know if you require any further assistance.

Which chemistry is used to create energy? *
Nuclear Chemistry
Organic Chemistry
Analytical Chemistry
Biochemistry

Answers

Answer:

*biochemistry* is the answer

Answer:

No the real answer is nuclear chemistry

Explanation:

A class is 47 min how many seconds is this ?

Answers

Answer: 2820 seconds

1 minute = 60 seconds

Multiply the value times 60

47×60=2820

what is the molar mass of CO^2

Answers

Answer:

44.01 g/mol

There you go, hope it helped!!!!!

A gas has a volume of 150 cm3. Convert this volume into mL

Answers

Answer:

The answer is

150 mL

Explanation:

To convert the volume from cm³ to mL we use the conversion

1 cm³ = 1 mL

So from the question

if 1 cm³ = 1 mL

Then 150 cm³ = 150 mL

Hope this helps you

What occurs when a solid substance dissolves into a liquid? 1 It stays solid and sinks to the bottom of the liquid substance. 2 It breaks down and becomes part of the liquid substance. 3 It stays solid and floats on the top of the liquid substance. 4 It changes the liquid substance into a solid substance.

Answers

Explanation:

When a solid substance is dissolved in a liquid such as water, the intermolecular forces of attraction between the molecules in the solid substance are overcome and they exist as ions in the solution. Hence the answer is 2.

The correct option is 2.

When a solid substance is dissolved in a liquid such as water, the intermolecular forces of attraction between the molecules in the solid substance are overcome and they exist as ions in the solution.

What is dissolution?

Dissolution is the process in which a substance forms a solution. Dissolution testing measures the extent and rate of solution formation from a dosage form, such as a tablet, capsule, ointment, etc. The dissolution of a drug is important for its bioavailability and therapeutic effectiveness.

What is an example of a dissolution?

Stirring sugar into water is an example of dissolving. The sugar is the solute, while the water is the solvent. Dissolving salt in water is an example of the dissolution of an ionic compound.

Learn more about dissolution here https://brainly.com/question/4529762

#SPJ2

DNA is a double stranded molecule. If one strand is ATCGATCGATCG, what is the sequence of the other strand?

Answers

i believe it would be TAGCTAGCTAGC A<—>T C<—>G

What does the mass of an object depend on?
A. Force of gravity
B. Temperature of the object
C. Time taken of an event to occur
C. Amount of matter that makes up the object

Answers

Answer:

D or the 4th one

Explanation:

mass is literally the measure of matter in an object which is essentially the weight or how much stuff there is.

Answer:

C:)

Explanation:

what is the most poisonous animal?

Answers

Answer:

That depends on what species it is

Explanation:

Like reptiles it is rattlesnakes

Spiders would be black widow

So it depends on the what species you what.

is helium gas a mixture or pure substance

Answers

An element is a pure substance as well, because if we fill up a balloon with just helium gas, it will only contain helium atoms. On the periodic table of elements, helium is element number 2 , and so that should tell you that it's an element of course.

A substance melting on the stove
is an example of a chemical
change
True
b. Flase
a.

Answers

Answer:

A. True hope this helped

When sugar is dissolved in water and mixed well the resulting solution is classified as a

Answers

Answer:

homogeneous mixture

Explanation:

Variable definition

Answers

Answer: is factor that change in a controlled experiment

Explanation:

A different student is given a 10.0g sample labeled CaBr2 that may contain an inert (non-reacting) impurity. Identify a quantity from the results of laboratory analysis that the student could use to determine whether the sample was pure.

Answers

Answer:

Melting Point.

Explanation:

In testing of a sample has impurities, we have to check the samples’s melting or boiling points or we a separation technique called chromatography.

Now, CaBr_2 which is calcium bromide is a White Hygroscopic Powder. Therefore it is a solid.

Now, a pure solid will always have a fixed melting point which means that it will melt completely at only one temperature.

However, if there are impurities, the melting point of a substance is affected in two ways:

-It's lower than than the fixed melting point

- It would melt at a range of different temperatures as opposed to a fixed temperature for the pure form.

Therefore, a quantity that can be used to determine whether the sample was pure will be melting point.

Which phrase is the best definition of science?

Answers

Answer:

Science is the information gathered through study.

Explanation:

Answer:Observation of the physical world.

Explanation:

If the pressure, volume, and the number of moles of a gas are known, which is needed to calculate the universal gas
constant from the ideal gas laul?
O the temperature of the gas
the molar volume of the gas
the molar mass of the gas
the partial pressure of the gas

Answers

Explanation:

temperature of the gas

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