# hellen

Most popular questions and responses by hellen
1. ## chemistry

An electron in a hydrogen atom makes a transition from an energy state of principal quantum numbers ni to n=2.If the photon emitted has a wavelentgh of 434nm what is the value of ni?

2. ## Chemistry

why is it important for company manufacturing vinegar to regularly check the molarity of its product?

3. ## Botse botse high school

Am a grade 10 learner n would like to know if i'll be able to become a social worker with the following subjects maths literacy , tourism , history and geography

4. ## Chemistry

The products for the following: CaCl2(aq) + K2CO3(aq) ¨ A. CaCO3(s) + 2KCl(aq) B. CaCO3(aq) + 2KCl(s) C. none of these D. no reaction

5. ## Electronics

Two resistors of 15ohms and 5ohms are connected in parallel.this parallel combination is connected in a series with a third resistor of 10ohms.the whole circuit is then connected across a 40 volts supply. 1.determine the resistance of the circuit. 2.the

6. ## Easy math

Eric has a 4 pound watermelon, 2 1/2 pounds of oranges, 3 pounds of apples, and a 1 1/2 pounds of grapes to make a fruit salad. How many pounds of fruit does he have in all? 1. 3 2. 10 1/2 3. 11 4. 15 1/2 Jeremy is baking a wedding cake and wants to be

7. ## Physics

a 4 kilogram ball moving at 8 meters per second to the right collides with a 1 kilogram ball at rest. After the collision, the 4 kilogram ball moves at 4.8 meters per second to the right. What is the velocity of the 1 kilogram ball?

8. ## physics

A 10kg box is attached to a 7kg box which rests on a 30 degrees incline the coeficient of kinetic friction is mk=0.1 between the box and surface find the rate of acceleration of the system

9. ## Chemistry

Aluminium react with oxygen to form aluminium oxide.how many grams of potassium chlorate V would be heated to produce enough oxygen to form 5.1grams of aluminium oxide

10. ## chemistry

Which reagents reagents to choose? The transformation shown below can be accomplished in TWO reaction steps. From the following list, select the two reagents (or sets of reagents) which would most effectively bring about this conversion. Reagents: 1. Conc

11. ## MAth

What should you say when you meet an angel

12. ## physics

Samantha is 1.21 m tall on her eleventh birthday and 1.32 m tall on her twelfth birthday. By what factor has her height increased?

13. ## Chemistry

The transformation shown below can be accomplished in TWO reaction steps. From the following list, select the two reagents (or sets of reagents) which would most effectively bring about this conversion. Reagents: 1. Conc H2SO4/heat 2. CN- 3. KMnO4 4. (i)

14. ## science

what does density mean in an easy way..! thank u

15. ## WG

i all ready did my work and i want to see if i got them right..... 1.what does a small blackened dot usually represent? Cities or towns. 2.which state contains the name of a country bordering united states? Canada. 3.what is the name given to the half of

hi for my english hw im suppose to find three ads for the same product one from 2006 one from 1980s-2000 and one from before the 1980s and showing how the ad has developed throughout the years, but the ad has to be provacative like the selling of a car

17. ## Physics

A satellite orbits the moon at height of 2000m.assuming it to gravitational pull of the moon,find the speed and time it takes for one orbit,given that mass of moon is 7.34 * 10 to power 22 kg and radius is 1.738 * 10 to power 6m.(g = 6.6 * 10 to power

18. ## life orientation

identifie 5 ways in which the environment /human factor impact on the community

19. ## WG

i all ready did my work and i want to see if i got them right..... 1.what does a small blackened dot usually represent?

20. ## Electronics

Rseries=R1+R2 =15ohms+10ohms =25ohms

21. ## math

31m^2n/41 x 21/mn x 2n^2/3m

1. ## algebra

I dont know

posted on December 6, 2017

Wbvsbd

posted on February 19, 2016
3. ## Botse botse high school

Thank u m.s sue you're the best

posted on June 30, 2015
4. ## Botse botse high school

Thank u ms sue . Wat are other careers i can take i hear that with the subjects lyk mine its hard to find a good stable job

posted on June 30, 2015
5. ## math

What should you say when you meet an angel

posted on May 29, 2015
6. ## Easy math

1. 11 ? 2. 7/9 ?

posted on January 20, 2015
7. ## Easy math

How I'm suppose to solve them? Like should I subtract, add, multiply

posted on January 20, 2015
8. ## Social Civics

for the first its A

posted on April 6, 2011
9. ## physics

An essay of how gravitational acceleration is used to benefit mankind and the environment.how can rural people also benefit from the use of gravitational acceleration?

posted on February 15, 2011
10. ## science

thx i got a c that's good anuff for me

posted on March 11, 2010
11. ## WG

2.which state contains the name of a country bordering united states? is it New mexico i checked again.!!!

posted on January 22, 2009