28. A runner completes a 10 km run in about 30 minutes. What was the runner's average
speed in km/h? Hint: (60 minutes = 1 hr)
a. 10 km/hr
c. 20 km/hr
b. 15 km/hr
d. 30 km/hr

Answers

Answer 1

Answer:

20 km/h

Explanation:

Speed = distance ÷ time

Speed = 10 ÷ 0.5 hours

Speed = 20 km/hr


Related Questions

sub-atomic particles like negatively charged electrons, positively charged

protons and electrically ________ neutrons​

Answers

Answer:

neutral

Explanation:

There are three basic subatomic particles. These are;

Protons (positively charged)Electrons (negatively charged)Neutrons (neutral)

A neutron has no charge unlike the proton and the electron. It is present in the nucleus and contributes to the mass of the atom.

There are 4 mg of lead present in 2000 g of a water sample. What is the
concentration of lead in m?

Answers

Answer: 130 ppm Pb

Explanation:

We use parts per million to express the concentrations of solutions that contain very, very small amounts, often called trace amounts, of a given solute.

More specifically, a solution's concentration in parts per millions tells you the number of parts of solute present for every

10

6

=

1

,

000

,

000

parts of solution. You can thus say that a

1 ppm

solution will contain exactly

1 g

of solute for every

10

6

g

of solution.

In your case, you know that you have

38

mg Pb

1 g

10

3

mg

=

3.8

10

2

.

g Pb

in exactly

300.0 g

=

3.000

10

2

.

g solution

This means that you can use this known composition as a conversion factor to scale up the mass of the solution to

10

6

g

10

6

g solution

3.8

10

2

.

g Pb

3.000

10

2

g solution

=

130 g Pb

Since this represents the mass of lead present in exactly

10

6

g

of solution, you can say that the solution has a concentration of

concentration

ppm

=

130 ppm Pb

−−−−−−−−−−−−−−−−−−−−−−−−−−−−

The answer is rounded to two sig figs, the number of sig figs you have for the mass of lead present in the sample.

The Kinetic Molecular Theory describes the behavior as well as the characteristics of an ideal gas. What are the five postulates of this theory? Provide at least 3 examples to describe these postulates.

Answers

Answer:

See explanation

Explanation:

The postulates of the kinetic theory of matter are;

Every substance is made up of tiny particles called molecules. Brownian motion and diffusion illustrates this fact.The molecules that compose matter are in constant random motion.There exists an attractive force between the molecules in matter. The attractive forces between gases are negligible. Solids have a definite shape and volume due to a high magnitude of intermolecular forces. Liquids have a volume but no definite shape due to weaker intermolecular forces. Gases have the weakest intermolecular forces hence the do not have both a shape and volume. They take on the volume of the container into which they are put. This illustrates this fact.The actual volume occupied by gas molecules is negligible relative to the volume of the container. The fact that gases are easily compressible illustrates this fact.Temperature is a measure of the average kinetic energy of the molecules of a body.

how did the report on the topic of climate change help the general public relate to the topic?​

Answers

Answer:

Report of the climate change can help the people. As when people wants to go for  picnics or somewhere else. They did not have any idea that what will be the climate when they go. Report of climate change help him to choose the right time for going on picnics or  somewhere else.

Answer:

The report mentioned ways that people’s lives may change because of climate change, such as rising sea levels, reduced crop efficiency, and heat waves. This information may encourage the public to change the way they use energy, for example how they heat their homes or power their cars.

Explanation:

answer 1-5 of lesson outline for brainiest

Answers

Answer:

see explanation

Explanation:

1. mid-ocean ridge

2.gravity

3.normal,reverse

4.cools

5.stripes

6.spreading

7.continents

These diagrams show two atoms of fluorine and an atom of magnesium.

On the left, a purple circle labeled F is shown twice, both times surrounded by 2 concentric circles. The inner circle has 2 small green spheres. The outer circle has 7 small green spheres. On the right, a purple circle labeled M g surrounded by 3 concentric circles. The inner circle has 2 small green spheres. The middle circle has 8 small green spheres. The outer circle has 1 small green sphere.
Which shows the correct steps in the formation of an ionic bond between these atoms?

A magnesium atom accepts six electrons from the fluorine atoms → Each fluorine atom donates three of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom accepts two electrons from the fluorine atoms → Each fluorine atom donates one of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a +2 ion → Each fluorine atom becomes a -1 ion

Answers

Answer: D

Explanation:

took test

Answer:

D

Explanation:

got it right  

what are the two components of a solution

Answers

The components of a solution are solute and solvent

Shaun's doctor has recommended that he consume 200 calories of protein a day. Shaun consumed 176 calories of protein in one day. How much more protein does he need to consume to reach the required amount? (1 gram of protein = 4 calories)

Answers

Answer:  Shaun must consume 6 more g of protein to reach the required amount.

Explanation:

Given : Recommended amount of protein = 200 calories

Now 4 calories = 1 gram of protein

Thus 200 calories = [tex]\frac{1}{4}\times 200=50[/tex] g of protein.

Calories consumed per day by Shaun = 176 calories

176 calories =  [tex]\frac{1}{4}\times 176=44[/tex] g of protein.

Thus Shaun need to consume = (50-44) g = 6 of protein to reach the required amount.

Shaun must consume 6 more g of protein to reach the required amount.

What form of electromagnetic radiation does gamma radiation use?

Answers

Answer:

Gamma-rays are a form of electromagnetic radiation, as are radio waves, infrared radiation, ultraviolet radiation, X-rays and microwaves. Gamma-rays can be used to treat cancer, and gamma-ray bursts are studied by astronomers.

Explanation:

Hope this helped Mark BRAINLIEST!!!

Gamma Rays are ionizing Electromagnetic radiation, obtained by the decay of an atomic nucleus. Gamma rays are more penetrating, in matter, and can damage living cells to a great extent. Gamma rays are used in medicine (radiotherapy), industry ( Sterilization and disinfection) and the nuclear industry.

How is activation energy represented on an energy diagram?
Energy
Reactants
Products
Reaction Progress
O A. Activation energy is the distance from the reactants to the top of
the "hill."
B. Activation energy is the distance from the top of the "hill to the
products.
O C. Activation energy is the final energy level of the product
molecules.
o
D. Activation energy is the starting energy level of the reactant
molecules.

Answers

In accordance with the diagram, activation energy is the distance from the reactants to the top of the "hill"

The activation energy represented on the energy diagram is as given as

"Activation energy is the distance from the reactant to the top of the hill"

So, the correct option is A.

What is activation energy?

The minimum amount of energy required by the reactant to do the reaction is called activation energy.

To learn more about activation energy here.

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What is the oxidation state of copper in Cu(C2H3O2)2? +2 -1 -2 +4 +1

Answers

The answer should be 5 cu

Theories must be supported by many lines of evidence.

True

or

False​

Answers

the answer to this question is true

Jack has a rock. The rock has a mass of 14g and a volume of 2cm3. What is the density of the rock?

Answers

Answer:

The density is 7 g/cm^3

Explanation:

The formula for density is p=m/V. Where p is the density, m is mass, and V is the volume. 14/2=7.

You have to make 500 mL of a 1.50 M BaCl2. You have 2.0 M barium chloride solution available. Determine how to make the needed dilution

Answers

Answer:

You need 375 mL of BaCl2 solution.

Explanation:

M1V1=M2V2

Dilution formula. Substitute known values and solve for V1.

M1 = 2.0 M

M2 = 1.50 M

V2 = 500 mL

(2.0 M)(V1) = (1.50 M)(500 mL)

V1 = (1.50 M)(500 mL) / (2.0 M)

V1 = 375 mL

How is oxide different from a neutral oxygen atom

Answers

Answer: The main difference between oxide and oxygen is that oxide is a chemical compound with at least one oxygen atom while oxygen is an element whose atomic number is 8.

Explanation: let me know if it was right or wrong

2 questions. will give brainliest if i can figure out how

What happens to the electrons of a reducing agent during a reaction?
a.Electrons are gained
b.Electrons are lost
c.Electrons are held
d.Electrons are doubled

When is a substance reduced during an oxidation reduction reaction?
a.After one substance is oxidized
b.Before one substance is oxidized
c.Same time as one substance is being oxidized
d.Only oxidation occurs

Answers

1= b. electrons are lost

2= a. after one substance is oxidized

A buffer is made with 0.493 M of the weak base methylamine ([tex]CH3NH2[/tex]) with 0.493 M [tex]CH3NH3Cl[/tex] (KA = 5.6 x 10^-4)

What is the pH of this buffer system?

If 0.100 M HBr is added to the buffer, what is the pH?

Answers

h^ ar hidrojen oksijen azot helyum

Is Chlorine and Sodium an Ionic or Covalent bond?

Answers

Answer:

It is an Ionic bond

. I am described as being conductive, malleable, shiny, and reactive with HCl. I am one of the most reactive elements. I turn black within seconds when I am exposed to air. If someone drops water on me, I will explode. When I do explode I send off characteristic purple-red (violet) flame. Who am I?

Answers

Answer:

Potassium

Explanation:

Most reactive metal in the reactivity series

The element in the question is referred to the alkali metal which is known as Potassium

Potassium is a highly reactive metal and reacts with Hydrochloric acid to

form a salt known as Potassium chloride and hydrogen gas.

Hcl + K ⇒ Kcl₍s₎ + H₂₍g₎

Potassium has a white color but when it reacts with water it explodes and

gives out a purple-red color as a result of the high excitation of electrons.

Read more on https://brainly.com/question/22993452

9 moles of Ammonia (NH3) are added to 50 L of H2O at a temperature of 29°C. The vapor pressure of water alone is 29.96 mmHg at 29°C. What is the vapor pressure of the Ammonia solution?

Answers

Answer:  The vapor pressure of the solution at [tex]29^0C[/tex] is 29.86 mm Hg

Explanation:

As the relative lowering of vapor pressure is directly proportional to the amount of dissolved solute.

The formula for relative lowering of vapor pressure will be,

[tex]\frac{p^o-p_s}{p^o}=i\times x_2[/tex]

where,

[tex]\frac{p^o-p_s}{p^o}[/tex]= relative lowering in vapor pressure

i = Van'T Hoff factor = 1 (for non electrolytes)

[tex]x_2[/tex] = mole fraction of solute  

=[tex]\frac{\text {moles of solute}}{\text {total moles}}[/tex]

Given : 9 moles of [tex]NH_3[/tex] are dissolved in 50 L or 50000 ml of water

mass of water = [tex]density\times volume = 1g/ml\times 50000ml=50000g[/tex]  

moles of solvent (water) = [tex]\frac{\text{Given mass}}{\text {Molar mass}}=\frac{50000g}{18g/mol}=2778moles[/tex]

Total moles = moles of solute  + moles of solvent = 9 mol + 2778 mol = 2787  

[tex]x_2[/tex] = mole fraction of solute  

=[tex]\frac{9}{2787}=3.2\times 10^{-3}[/tex]

[tex]\frac{29.96-p_s}{29.96}=1\times 3.2\times 10^{-3}[/tex]

[tex]p_s=29.86mmHg[/tex]

Thus the vapor pressure of the solution at [tex]29^0C[/tex] is 29.86 mm Hg

helppppp will mark brainlest

Answers

Answer:

if you will decrease the HCO3- so the less H+ ion will be form and reaction will more likely shift to product and when HCO3- decreases pH value increases and vica versa for the increasing HCO3 the more H+ ion will be form and reaction will shift to product and the pH value will decreases!!

I've doubt in reaction shift coz whatever is the amount of HCO3- this is completely gonna form number of H+ so reaction shift may or may not be same!!

Certain race cars use methanol (CH 3 OH) as fuel. The combustion of 9.8 moles of methanol produces what mass of water?

Answers

The combustion of 9.8 moles of methanol will produce 352.8 grams of water.

Stoichiometric calculation

First, let us look at the balanced equation of combustion of methanol:

[tex]2CH_3OH(l)+3O_2(g)-- > 2CO_2(g)+4H_2O(l)[/tex]

The ratio of number of moles of methanol burned and that of water produced is 1:2.

Thus, 9.8 moles of methanol will produce 19.6 moles of water.

Mass of 19.6 moles water = 19.6 x 18 = 352.8 grams

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IBNEED HELP ASAP
NO BULL I NEED ACTUAL HELP

Answers

Answer:

god says dont use any assault language okay?

Explanation:

You weigh out 0.1183 g of a complex salt to analyze for the percentage of cyanide ion in your complex salt. After dissolving the complex salt in solution, you determine that it takes 10.02 mL of a 0.08035 M potassium permanganate solution to react with all of the cyanide ion in your complex salt. Using the balanced chemical equation provided, determine the mass percentage of the cyanide ion in your complex salt. (Remember: the mole ratio of MnO4 - to KMnO4 is 1:1)

Answers

Answer:

25.35%

Explanation:

Again let me restate the the equation of the reaction;

H2O (ℓ) + 2 MnO4 - (aq) + 3 CN- (aq) → 2 MnO2 (s) + 3 CNO- (aq) + 2 OH- (aq)

Amount of potassium permanganate  reacted = 10.2/1000 * 0.08035 = 8.1957 * 10^-4 moles

If 2 moles of MnO4 - reacts with 3 moles of CN-

8.1957 * 10^-4 moles of MnO4 - reacts with 8.1957 * 10^-4 * 3/2

= 1.229 * 10^-3 moles of CN-

Mass of CN- reacted = 1.229 * 10^-3 moles of CN- * 26.02 g/mol

= 0.03 g

Hence, percentage of the cyanide = 0.03 g/0.1183 g * 100

= 25.35%

What does a negative AH tell about a reaction?
A. The reaction absorbed heat.
B. The reaction has no enthalpy.
C. The reaction is exothermic.
D. The reaction is endothermic.
SUBMIT

Answers

When delta H is negative, it means the products in the reaction have lower energy compared to the reactants, so the reaction has lost energy and released it as heat, making it exothermic.

Answer:

The reaction is exothermic

Explanation:

How many moles of H,O must be decomposed to form 200 moles of H,?
24,0 2H +0,

Answers

Answer:

300

Explanation:

at least 300 molecules

Of the following elements aluminum, magnesium, aluminum, silicon, and sodium which has the smallest atomic radius? Explain your answer.

Answers

Answer:

Sodium

Explanation:

Radius grows as you go down and to the right on the ptable.

the form of energy that your lunch represents is?
A) electrical
B) chemical
C) thermal
D) nuclear

Answers

The answer is B. Have a good day.

seaborgium mass number =

Answers

Explanation:

seaborgium Is a type of corn that is grown in warm countries.

answer is SG

Answer:

269 u

Explanation:

can we observe a lunar eclipse during a new moon phase? explain your answer.

please help me thx

subject is science

Answers

Answer: There is no eclipse. However, two or four times a year, the Moon travels through some portion of the Earth's penumbral or umbral shadows, resulting in one of the three types of eclipses mentioned above. When the Moon crosses between the Earth and the Sun, this occurs. This is only possible when the Moon is in its New Moon phase.

Explanation:

HOPE THIS HELPS!!! : )

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